More on First Scopes

Hi all I have been thinking about first scopes for the past couple of days. I have put together this pin-board to refer people too in the future. The problem with first scopes is complicated so I think it would be best to put all of my thoughts down on paper. (so to speak)

It is a cliche at this point to point out that there are a bunch of really bad options for your first scope, but these generally fall into the category of a small refractor (50-90mm in aperture), it could be on an equatorial mount or not, it could also have a clock drive. None of the bells and whistles matter, whatever you do do not buy an instrument for visual use that is in this aperture range. The problem has to do with the fact that while they are light and portable you cannot see anything with them. Usually they have terrible quality optics but mostly the problem is that the sky will swamp out anything other than the brightest of objects in the city.

Now your going to ask me why I don't have any Catadioptric Telescopes on this list, the reason is that there focal lengths are so long, but mostly it has to do with the way they are mounted. No initiate amateur should ever deal with an equatorial mount, the set up is too complicated resulting in whole nights wasted trying to make things work. The only other option is a fork mount and there we have a whole other set of problems. Since forks grow with the aperture of the telescope you are restricted to single arm fork mounted telescopes 8" in size if you are going to use it more than once or twice. This is a hard truth to understand but the fork is both heavy and weirdly shaped resulting in it being uncomfortable to carry. This means that you won't use your telescope. Don't believe me? Go to ebay (or Astromart) and search for the phrase "only used once" or "only used once or twice" when looking for a telescope.

While we are on the subject, you may think that you will get a deal buying second hand telescope. This is a terrible idea for the following reason, you don't know who owned it. Telescopes are sensitive instruments meaning that if they are misused or mishandled in any way they may require costly repairs or be utterly unusable. For the most part GOTO scopes will have issues with there motors and gears, Newtonian telescopes will require collimation. These are issues you do not want to have to deal with without a stout warranty and some guidance.

The truth is that the only way your going to get into the hobby and staying in it is to have a telescope that performs well visually while at the same time being portable enough to take into your back yard at night. This leads us to the Dobsonian telescope. Basically you take a Newtonian telescope put some castors on the sides of it and put it on a rotating platform and you have an altitude-azimuth telescope. Add optical encoders to each axis and a computer and you have something that can be used to tour the sky with relative ease.

For the impatient this is the best option in less than an hour you will have your telescope setup and be exploring the sky with 6" or 8" of clear aperture. You won't track objects but you will be able to find them. If your a patient person then I would suggest something without the computer, since it will enable you to learn the sky the hard way, finding objects by star hopping.

I would not recommend GOTO telescopes for your first scope. Why? Because they are pieces of technology, slightly anachronistic since they have a digital computer, only in the most rudimentary sense. Usually GOTO telescopes end up being unusable, leading to a great deal of frustration with no objects being viewed through the scope.

Now the last and most important tip is this, Amateur Astronomy is a frustrating hobby no matter how you do it. There are very few shortcuts that don't end up being headaches at some point. The point I am trying to make is that perseverance is a necessary and sufficient condition no matter which road you chose to make astronomy your hobby.

Signal and noise

Hi all, I owe you a blog post but I have actually been busy. The surgery stuff is progressing I still don't have a surgery date and I am still massively frustrated with the disaster we call an insurance industry in this country. However I am not going to complain about that I am instead going to complain about something else.

When you don't have a telescope for astrophotography you spend most of your time researching which telescope to buy. Such things occur naturally with hobbies, since the goal is to chase the dragon for the most part. Its strange the first money out the door is going to be spent on a car, an old Subaru Legacy 5 speed (hopefully) then comes the telescope, then comes the software for the telescope then comes the computer upgrades.

My point is that planning is the only thing I can do and part of planing is research. The problem with research is that because the community is small there is a lot of superstition being perpetrated as fact. The best example of this I have come across is focusing.  Astrophotography is part art part science. The art is in the photographs, the science is in the planning on how to get to the photographs. When it comes to actually taking picture I anticipate trouble in two actions, the first is in polar aligning the mount, this must be done any time you move the telescope to a new location or break it down and set it up. The problem with polar alignment is that it is complicated and you want to do it well, this may mean taking a couple of hours to polar align your mount. The methods for polar alignment are not all that controversial.

However the second place I think I will have issues (and by I, I mean all astrophotographers) is focusing the telescope and keeping it focused. There is a great deal of information about focusing some of it might not be all that useful. The problem comes in that for the most part telescopes bend light so it comes to a focus, how they do this is very much dependent on the length that the light has to travel. The problem is that focusing needs to be exact, the goal is to get stars as small as possible on the imaging medium. You can do this crudely by hand, but most go to some sort of mechanical help for this, then there is the problem on thermal expansion. See most objects length changes with temperature, the result is that your focus (the place where your stars are smallest) moves as the temperature changes. This also means that the spacing of your lenses changes as temperature of the cell holding them does.

This could result in a lot of painful problems, not the least of which is people telling you that you should not get a carbon fiber telescope tube for a refractor since the lens cell is designed to compensate for changes due to thermal expansion. This is however a third order affect, the expense of getting a carbon fiber optical tube is a first order effect on your wallet. The interesting thing is that you should probably refocus periodically anyway because your never going to be sure where the best focus is.

Let me explain, when I was talking with my friend and mentor about this issue he asked me this question, "Where are these people going to get 0.5" seeing?" In order to see the effect of having a carbon fiber tube you would have to have really nice skies, since the is not a uniform object, its temperature and speed vary we get tiny lenses forming in the atmosphere as the local air changes, this is called seeing. Seeing acts like little lenses dancing in front of your objective, resulting in stars twinkling. More than that it is something you can measure with your camera, since even when focused the seeing smears out stars on your image plane.

Seeing effects your images much more than any choice of optical tube material. So don't worry about what your optical tube is made of unless your going to launch it into space. This has also made me leery of talk of a critical focus zone on a telescope, maybe a reader can explain why between actual thermal expansion and seeing I should worry about my focuser moving a few microns?

Frustrations

This post is an update. I am inching closer to a surgery date I think. The problem is that I need approval from my insurance company and they in turn need for me to complete my multidisciplinary pre-surgery regimen. The strange thing about this is, they think that in 90 days I will somehow learn some trick (and it would have to be a trick)  to shedding weight that has eluded me for 20 years. I don't know what the pre-surgery regimen is about to be quite honest.

I also have learned that I suffer from very severe sleep apnea. For those of you who know me you understand that I drink quite a lot of caffeine and I am still tired during the day. This is the result of not really being able to get a good nights sleep. Apparently this has been going on for years, so now when I wake up tired I know why. However, I cannot stand going to sleep knowing that its near useless for me, I want to get on with my treatment, figuring out what works so I can go on with my life! The thing is that I need a CPAP machine and the only way to get one is to wait by my phone until they call. It is a special kind of torture to tell someone they have a major sleep condition, and not help them get treatment for 4 days because its a weekend.

Some of the Nitty Gritty of Expeditions (With first scope advice!)

Hi all, Its been awhile. Sorry I  haven't posted, but its hard to think of pithy things to say when your on your back in a CT scanner. Anyway I have had substantial interest in the Astrophotography Expeditions so I think its a good time to talk about some details. (Subject to change since the first expedition is over a year away.)

 The idea is that as long as your willing to bring your own food and gear for you and yours you are welcome. We should have multiple vehicles since I can only carry one person other than myself. The idea is that there will be multiple tents, mine will be for gear and maybe 2-3 people other than myself. We will get together before hand to make sure there is tent space for everyone. Individuals will be responsible for there own sleeping bags and pillows. Now since there will be astrophotography it is going to be natural to ask the question of what other are supposed to do at night.

 I would encourage people who are bringing there own vehicle to bring a scope. This leads me to a question I get asked a lot, which is basically what kind of telescope should I buy. Since we will be under dark skies it will be an opportune time to explore the night sky. The scope I think everyone should start of with is a Dobsonian. My personal recommendation is to go to Orion Telescopes and Binoculars for your first dob. I started out on a 6" and had a blast under suburban skies, so it I would say a 6" Dob would be the low end. Now if your willing to save a bit of money I would actually recommend the XX12i Truss tube, as it will be easy to transport and give you better views at the eyepiece. The computer will give you instant gratification, by pointing you at objects and giving you tours of the night sky, but to push yourself  and get better at astronomy you need to try star hopping to your target. Finally if push comes to shove a good pair of 7x50 binoculars can give you great views without the hassle or the expense of a scope.

If you have some experience with using a telescope and your poison is taking photos of the stars and planets, well I don't really know what to tell you since I cannot recommend my setup to anyone yet. I mean stay tuned for test reports but until I actually have the scope and camera and try it in my backyard or in a field, I cannot say for certain its the right way to go. If your a novice just starting off I would go with the Orion Sirius 80 which is sort of the standard telescope to start out with for astrophotography. As for a camera, I would start of with an unmodified Canon EOS. (t3 or t3i) This will give you a taste for astrophotography.

Now you may be saying, Aaron none of these scopes are what you would buy, and that is correct. However I am not a novice, I am a journeyman. (or at least I tell myself that) I am configuring a modular system for specific targets. When the time comes you may want to do the same, these suggestions are for people beginning there journey.

I would like to reiterate that I do not recommend people jump right into astrophotography, its hard enough when you have a vague notion of what to do, its is impossible if you do not know if you have the target you are interested in in the Field of View of your scope.

The elusive block 3

Hi all,

In case you were wondering what on earth was going on with my previous blog post. There was a section about a Block 3 version of my astrophotography setup. This was an insanely expensive TEC refractor paired to a super expensive Paramount MX. ( I am fighting not to use the adjective astronomical anywhere on this blog.) Instead of a redo of my mount and telescope in Block 3 I have decided to just buy an APO in Block 1. Block 3 initially disappeared  but now I have added a new upgrade, to a 35mm Starlight Express camera with narrowband and  LRBG filters. This may be years down the road so stay tuned.

Going Modular

I owe you all an astrophotography post. This Friday while I was waiting to be hooked up to a bunch of sensors so strangers could watch my bodily functions as I slept, I was reading a book called The New CCD Astronomy. I must admit I was terribly disappointed. The main problem with the book had to do with the fact that it was written in 2002 thus it was for an outmoded world.  Since this book has come along, we now have inexpensive mounts which can carry 40 lbs, and digital SLRs capable of astro imaging. The result is that the book was mostly useless about buying equipment.

My last post on astrophotography was a rant against what is colloquially called Aperture Fever. (Not having to do with inhaling moon dust) Many might be wondering if I am only going to tell people how not to do it. Well, here is my plan for astrophotopgraphy,

Equipment (Block 1) - The idea here is to go with a modular setup that requires a little extra planing before expeditions, so initially we will go with a 5" Apo Refractor, 80mm Guide scope, mount and Digital SLR. This setup will be both portable and sturdy, the mount being weighted about 2x what it is carrying. The goal with this setup will be to capture the nebula in and around M45.

Tech Upgrades (Block 1) - This is just enough gear to be able to take photos and reduce them once we get them back. A Macbook Air with Nebulousity for image capture in the field, then a 4k+ screen for reduction and photoshop finishing.

Equipment (Block 2) - A 180mm Maksutov-Cassegrain telescope for long focal length work, planets along with other objects. This setup will be excellent for my second favor ate deep sky object, M51.

Tech Upgrades (Block 2) - The idea here is to build a bad ass gaming/number crunching/image processing machine.

In case you didn't notice I am a huge fan of the Apollo program, Once all Block 1 purchases have been made I will move onto the Block 2 purchases.

No pain & humiliation, No gain.

There is a popular perception that the type of surgery (gastric bypass) I have elected to undergo is somehow an easy way out. A method for lazy people to become thin. That perception does not align with reality in anyway. I have completed a sleep study, I am both invigorated and exhausted.

This issue with the surgery is that its not in and of itself the end of the process. A gastric bypass will affect you for the rest of your life, however it will not in and of itself keep your weight off. Even to get to that point though, unless you are very wealthy, you have to undergo 3, 6, or 12 months of supervised dieting, this is where some are caught out because if you loose enough on the diet you will be denied the surgery. Then you need three clearances, a cardiac clearance, a pulmonary clearance, and in many cases a psychiatric clearance or nutritionist clearance.

The sleep study was for my pulmonary clearance, the would like to know if you have sleep apnea before you go under the knife. The main problem with a sleep study is that you are expected to go to sleep wearing sensors all over your body, then they put a Bane like mask that forces air into airway half way into the night. If you do anything like get a normal amount of sleep the day before your study, you won't sleep very much. The result is somewhat paradoxical, how do you get data about a persons sleep if they aren't really sleeping?

Anyway I do have sleep apnea, more than likely, but it will not keep me from having the surgery. The interesting thing about this process is that you are poked and prodded to within an inch of your life, before they let you go under the knife. You then endure a review of your psychology from someone who give you a battery of tests then spends an hour judging you. My clearances will be done by the middle of august, from there its the last month or two of a supervised diet, then I will get a surgery date.

My friends, do not worry that I am going to go around evangelizing weight loss surgery after I have had it done. The truth is that its a hard choice and its not for everyone, if you are willing to endure the humiliation and pain, the prods and the frustration, then maybe it is the right option for you. But if I have learned anything in my years on this planet its that there is no one size fits all solution, everyone must use the understanding of themselves and their situation to make the best decision that they can.

A Rant About Aperture

There is a scourge in amateur astronomy and it is the notion that you need a big telescope. The argument goes something like this, the larger the light collecting area of your the more you can see visually, and the shorter your exposure times will need to be. This is the type of conventional wisdom that gets people into a lot of trouble.

In order to image you must compensate for the movement of the earth, the result being that you need a mount or platform to track the area of the sky that you are trying to look at or image. This leads to a problem since equatorial mounts have weight limits. The result is ridiculously large mounts and telescopes, or telescopes with equatorial platforms.

This leads to a razor I have come upon in my time as an amateur astronomer, the number of times per year you use your telescope is proportional to its moment of inertia. As evidence I present the preponderance of used telescopes on astromart that say "used a few times" or "only used once." My personal experience had to do with the purchase of an 10" LX-200 ACF  which really should not be handled by one person. While sturdy in Alt-Az mode, the telescope weighted so much that I could not bring myself to use it that often.

Indeed a large swath of telescopes I would simply not recommend for this reason. Any telescope on a fork mount is cumbersome over 9.25" it is quite nearly impossible for one person to set one up safely. 8" telescopes have been used for time and memorial but we now come to the elephant in the room, what are you using this thing for exactly?

If you are using it for visual astronomy, you will be constantly let down since almost all deep sky objects that you see on APOD or in text books have been taken with some sort of digital camera. The result is that at the eyepiece you see almost nothing or something lacking contrast and color. The end result of any attempt at satisfying visual astronomy leads to a truss tube Dobsonian over 30" in diameter. We then come to the other elephant in the room which is the fact that you cannot use such an object anywhere near your home, unless you live in the middle of nowhere.

Hence, Visual astronomy is a hard nut to crack so that you end up with a very large telescope which is as complicated to set up as an equatorial telescope and that you can only  use once or twice a year at a dark site. The other option is to go to imaging, which you can do with a modest setup, which you cannot under any circumstances use for visual astronomy save for the occasional dark sky expedition. The reason that aperture does not matter for imaging is that your interested in collecting enough photons. The way you collect the photons is usually with sub frames and a digital camera far more sensitive than your iris. So you must pick your poison, either you have a light imaging setup or a big dob you lug to dark skies, anything in between is just a waist, for anything except viewing planets of course.

The reason I am posting at 4:42am on a Friday is that I have a sleep study tomorrow, so I have decided to stay up until its time to finish that.