Adapt or die

[Totally_Computerized]

Hey guys , first post for me. So hello everyone !

My question is..... Iam getting my first telescope this xmaz , ive settled on a skywatcher 200p for various reasons . I know its not a AP telescope or so ive been told . But I have a canon 70d , and I would love to get some use out of it with the scope . The issue ive seen is focusing. So I was wondering what t rings, t adapters , extension tubes and so on will I need to achieve focus . Oh and why Iam here , is the telrad finder scope any good , I want to make the star hopping as easy as possible to impress the mrs so I can talk her into me getting a EQ5 mount in the future !

[John]

Hi and welcome to the forum !

Do I take it that you are getting the Skywatcher 200P dobsonian ?

The Telrad is extremely good and an excellent addition to a dobsonian. It does make star hopping much easier. Having a good star atlas helps as well !

Can't help you with the imaging because I'm a visual observer but many on this forum do image so help will be at hand on that soon !

 

[discardedastro]

The 200PDS is absolutely a capable AP telescope - but the mount makes it possible. It's not a great 'scope for planets, though it can do that. What are you looking to photograph? What sort of images really attract your interest? Wide-field, deep-field, planetary?

Get a copy of Turn Left at Orion (in advance of buying, if you ask me). "Every Photon Counts" is another great book for beginners of AP and a great resource.

In terms of achieving focus with any camera the basic idea is to put the focal plane at the focus point. The back focus on a 200PDS is quite generous, so you'll need an extension tube - one 2" extension is supplied with the scope and that may suffice. You'll either need a 2" to T2 connector adaptor as well as a T2-to-Canon-mount adaptor, or you can go direct from Canon to 2" - I'd go for the T2-mount adaptor as you'll find that things like coma correctors and filter wheels commonly use the T2 thread/format. Baader also do a thing called a "Varilok" which is a variable extension tube that's quite handy to get the backfocus set perfectly if you do put a coma corrector in, for instance.

My 200PDS uses an ASI183MM - this has very little backfocus (11mm) from the thread to the sensor. This is attached to a filter wheel, then a Varilock, then a coma corrector. The coma corrector has a 2" front so drops straight into the focuser, without an extension. That all sums up to around 65mm of length, which lets me achieve focus. With an SLR you may have to aim for much less length depending on how far back the sensor is - on my Nikon D1X that's about 56mm, on the Z6 it's much less. So it really does depend on the camera.

[JOC]

I have a 200P flextube.  With no adadpters other than those supplied with the scope I just added a T ring to the front of the camera body (I have a Canon Rebel T3 (1100D)) and this goes into the standard focus unit with one of the supplied rings and I get focus without issues.  HTH

Edited November 20, 2019 by JOC

[Robny]

There are lots of reports regarding people not bring able to get focus with there cameras on s 200p due to not enough inward travel.

However....as above from @JOC therr are also people that achieve focus with no issues.

Best thing to do is give it a try, if you dont get focus, chances are with a 200p is because of not enough inward travel.  You may get lucky and be fine!!

If you have a problem with inward focus with your camera, then it may need a change of focusser for the slimline version.

Oh and btw.....welcome to the group!!!

[bottletopburly]

If you buy a new 200p with duel focuser you get as standard a 1.25” eyepiece holder it is a two part adapter if you unscrew the barrel top piece you are left with a 2” base part all you need now is a t ring  to attach to your camera https://www.firstlightoptics.com/adapters/t-rings.html Then the base part will screw into this  , now insert into draw tube do screws up and your ready  , on my 200pds with a canon 1000D  approx 22mm of draw tube would be showing  using a bahtinov mask you will get focus spot on .

[Totally_Computerized]

Thanks for the super quick response guys.  Its the 200p on a dobsonian mount i will be getting . Already have making every photon count and turn left at Orion arrived this week so i get an idea of what i will see with the scope . Ive done some basic AP with my camera and a tripod and 10 sec shots that i was fairly happy with . I guess my issue is the confusion of how things can go together on the scope having never been hands on with one i.e can i put a barlow lens infront of my camera , is that a pain to image with , stuff like that . I was blown away with what i managed with just my camera and a tripod,  and iam the type who just stands around looking up with wonder most of the time ( much to the mrs annoyance) so having a telescope is something i want to get the most out of . Sorry if that sounds a little romanticized ha 

[Rob Sellent]

36 minutes ago, Totally_Computerized said:

Sorry if that sounds a little romanticized

Not romanticized at all I think it is that 'wonder' which drives all of us into this wonderful hobby. I'm not an imager but if you have any questions, worries or concerns, I'm sure you'll get responses almost immediately. Visually speaking your 8" Dob is going to be lovely. There are so many winter treats to enjoy that I guess only the cold and clouds will keep you away. Again, if any questions or concerns crop up, just let us know and I'm sure you'll get help straight away.

Welcome to SGL and I look forward to meeting you on the boards and reading about your new adventures

[david_taurus83]

Is it a tracking dob base? If so then you should be able to take some short exposures and see how you get on. A 1m/1.2m focal length scope is not an easy entry into AP though. I know cause I tried. I had to get a large mount (AZEQ6) to get reliable tracking and guiding with an F5 200P. An EQ5 is too small for a 200P really.

[JOC]

@bottletopburly that was exactly what I did, took apart the 1.25 adapter and you do indeed get the ideal ring needed to connect to the camera T ring 🙂 My avatar moon was taken with that setup.

[joe aguiar]

  The telrad is considered to be one of the best finders. If u get into imaging u can just buy rings and a eq6 mount.

I would recommend maybe for a month or 2 just try visual and get used to how a telescope works focus, understand ep power, Constellations where things are in the sky. How the sky moves etc then try imaging?

 

[Totally_Computerized]

Do you guys think it would be better to just get a camera phone holder and work with that for some moon and planet AP , insted of worrying about trying to attach a dslr ? 

[Space Hopper]

Well you could, but odds on you'll be disappointed with the results.

[Raph-in-the-sky]

13 minutes ago, Totally_Computerized said:

Do you guys think it would be better to just get a camera phone holder and work with that for some moon and planet AP , insted of worrying about trying to attach a dslr ? 

I know it's a popular piece of kit but to be honest, I don't see the point of buying one to get a couple of decent pics of the moon and a few terrible pics from jupiter/saturn. Some will disagree.

[Raph-in-the-sky]

Oh... and Telrad is GREAT!

Telrad + 9x50 RACI (right angle corrected) is a very efficient and popular combo for Dobs

[JOC]

Get a T ring for your camera, they are not too costly and make attaching the camera really easy.  It's a question of what you really want to do.  Imagers see a question about taking pics of the night sky and often seem to automatically assume that everyone wants to track sky for hours and hours of subs, and stacjing and multiple filters to obtain their stunning results.  However, not everyone wants to do this.  I just wanted to have a play and see what I could achieve with what I had and modest possible additional outlay.  I can attach my camera to the focus unit as we have been discussing and also to the back of my Morpheus EPs and can take the moon and have a bash at the larger planets.  I've also learned how to take a pretty decent picture of a constellation with just my camera on a tripod and had a play with stacking exposures.  I therefore have photos good enough to impress family and friends who don't really know what it could look like and I have fun with it.  Isn't having fun what it is all about?

[Totally_Computerized]

I mean the reason I came here was because I got shot down in flames on reddit for trying to ask the same questions as I have here . I do understand real AP though its expensive,  time consuming,  and can be frustrating. 

Ive had my make every photon book for four years , ive tried to take as long as possible to make a decision on a telescope because iam an impulse buyer , but ive spent alot of my 39 years looking up , and so i want to take that up a level . I really want to do some AP but not at a serious level because truth be told I cant afford it , nor have the time . But I dont want that to hold me back to do some basic AP . I definitely wouldnt be going out buying a £800 camera to use with a dobby , but as ive already got a dslr ......... Anyway , iam going to buy my scope next week hopefully may be a sale on somewhere , i still have a ton of questions about clip in filters for light pollution and moon filters and stuff but you guys are probably tired from reading all this anyway !

[joe aguiar]

1-with a dob you can only do moon and the few bright planets

2-next step would be get a eq mount maybe eq6 for the scope polar align and with the goto you can do 30 to 40 sec unguilded and be ok since its tracking u might even get to 1 min.

3-after that u need to guild or get a auto guilder to prevent star trails or boated stars.

so the first step you are there just need a t ring and or adptor

the 2nd step is kinda easy too but that mount on used market where iam about $1000 used, I think that's about 600 your money but check that out, this is also not so hard.its when u get to the 3rd option that it becomes expensive with camers auto guilders good tracking goto mounts

joejaguar

[John]

52 minutes ago, Totally_Computerized said:

I mean the reason I came here was because I got shot down in flames on reddit for trying to ask the same questions as I have here . I do understand real AP though its expensive,  time consuming,  and can be frustrating. 

Ive had my make every photon book for four years , ive tried to take as long as possible to make a decision on a telescope because iam an impulse buyer , but ive spent alot of my 39 years looking up , and so i want to take that up a level . I really want to do some AP but not at a serious level because truth be told I cant afford it , nor have the time . But I dont want that to hold me back to do some basic AP . I definitely wouldnt be going out buying a £800 camera to use with a dobby , but as ive already got a dslr ......... Anyway , iam going to buy my scope next week hopefully may be a sale on somewhere , i still have a ton of questions about clip in filters for light pollution and moon filters and stuff but you guys are probably tired from reading all this anyway !

What scope does the book recommend to get started in imaging ?

Probably not a 200P dobsonian to be honest with you.

There might be better choices that will enable you to graduate more smoothly from some visual experiences to imaging. The optical tube from the 200P dobsonian can be removed from the dob mount and put onto an equatorial mount but you will need a pretty heavy duty mount for imaging purposes because the dob optical tube is an F/6 wheras the one that comes on the equatorial mount is F/5 (shorter).

Perhaps just hold back a little while longer from actually commiting to a scope ?. You won't get shot down in flames here, just lots of good advice

[Rob Sellent]

42 minutes ago, John said:

Perhaps just hold back a little while longer from actually commiting to a scope ?. You won't get shot down in flames here, just lots of good advice

Aye, wise words

@Totally_Computerized:From my extremely limited understanding - as a visual observer - it often seems to me that visual and imaging require opposite necessities in many respects.

For example, for the visual observer the brightness of a given deep space object (DSO) is dependent on aperture whereas for the imager the signal or brightness of the image depends on the focal ratio of the scope. An f/5 8" scope will produce a brighter image for the visual observer than an f/5 80mm scope but curiously, both these scopes will provide the same brightness image per pixel for imaging. Sure, the 8" scope will offer more resolution but I think unless this can be put to use with well suited cameras and imaging gear it probably goes to waste.

Again, for the sake of argument, the mount is to the imager what aperture is to the visual observer. For the visual observer the question would be, "Can I pick out detail from the object being observed?" For the imager, "Can I track the object accurately?"

For guiding over a period of time an EQ mount is necessary but large Newtonians plus all the necessary assessories for imaging would place huge demands on the mount. Not only in terms of the mass involved but also in terms of the scopes' focal length. I've read about imagers using 5" Newts on an HEQ5 , but for an 8" something like an NEQ6 Pro would be needed to keep the tube and imaging gear rock steady.  

Combining astrophotography and visual astronomy will more than likely lead to an EQ mounted Newtonian probably no bigger than a 6" to start off with but as with all things, compromises will be made. Visually, aperture is very important but for imagers bigger is not necessarily better, and is the reason why so many imagers end up choosing relatively light and fast 80mm APO refractors for astrophotography.

[Totally_Computerized]

Oh iam mind made up on a dob even if i cant AP its been to long already ha . I just wanted to see what could be achieved.  Has anyone any experience with the skywatcher star adventurer pro or similar mounts as i could just get one of those for use with the camera and maybe a small refractor i think the weight limit was about 10 pounds . 

[joe aguiar]

most important thing is mount most people get a heq5 is rock sold and good tracking/goto

a skywatcher 80mm evostar apo is a good refractor for that just add a focal reducer and there may have to change focuser to something more solid.

you can try finding a used SWED or something similar well in fact even try looking for a used HEQ5 mount too.

then again after that u need a camera but u have that, then a guilder or autoguilder/filters etc it starts to add up. u may need a laptop and a powertank for power unless u can have a cord from the house.

even getting this used mount and scope used still can run $1500 cdn maybe that's 1000 UK but u understand still not cheap

joejaguar

[Skipper Billy]

43 minutes ago, Totally_Computerized said:

Has anyone any experience with the skywatcher star adventurer pro or similar mounts as i could just get one of those for use with the camera and maybe a small refractor i think the weight limit was about 10 pounds . 

I bought one recently just for a giggle really but I have to say I am really quite impressed with it. With reasonable polar alignment and a Canon 70D with a 200mm prime lens I can get 40 seconds unguided with reasonably trail free images.

Its really good fun!!

I can also use it set at 90 degrees for slow scanning time lapse!

I would suggest its a good intro to imaging without spending much money.

[Totally_Computerized]

I probably will go that route then , I only have two lenses for my 70d the variable that came with it and the 50mm that everyone buys when they have a canon 😁 Iam going to see how I go with the dobby then and start saving for a mount .

Are the Phillips planispheres worth having while using a dobby , I watched some videos on how to understand them , but are the useful in practice?

[Rob Sellent]

49 minutes ago, Totally_Computerized said:

Are the Phillips planispheres worth having while using a dobby

This is for general consideration only, not to overload you with information:

• get yourself a decent star map. I find the Pocket Star Atlas by Sky and Telescope indispensable. It's not that expensive, it's a piece of art in itself and it is extremely useful. The first pages have a kind of overview of the night sky's constellations so a planisphere isn't necessary.

 

• at some point you might find yourself wanting to upgrade the view finder. I have found that Skywatcher's 9x50mm is the business and it ought to be the right angled correct image one. It will deliver stars down to about magnitude 8 and when you move amongst the stars following your atlas, your left is left and your up is up.

 

• a Telrad or Rigel finder will also be a big help in star-hopping. Position the bullseye, or the other two rings in the proper place against the stars and you’re more or less done. If you're out a little you can work out where you are by the three ringed cirlces giving you varying degrees of the sky you're looking at. The only negative point about the Telrad or Rigel is that they can’t deliver more stars than your eyes alone can see, so if you're in an LP area, they really do speed up your finding, really do help to judge where you are, but it must be used in conjunction with the findercope.

 

• at some point you might find yourself itching for more eyepieces, but take your time! Use your gear first and get to know what you're looking for and what you need. With that said a low magnification EP is often handy for finding DSOs. The low mag EP should offer you sufficient sky to manage along with your star map and it will hopefully pick out or hint at what you're hunting. For an 8" f6, you don't really need more than 3 eyepieces and a x2 Barlow. An eyepiece in the range of 10 to 12mm, something in the range of 14 to 16mm and a low power 24mm. There's no need to be blowing loads; scan the secondhand market for two decent eyepieces and a Barlow and you're pretty much sorted.

 

• do check out sketches. They are often overlooked, but they ought to be viewed. NASA photos or those produced in the imaging sections here are not going to help you visually. Sketches are generally produced by patient observers who are trying their best to get what they see right. As such, the drawings should give you a very good idea of what the DSO will more or less look like in your eyepiece.

 

• your scope will need collimating on every session. So whatever else you do, you must budget for a Cheshire type of eyepiece or collimating cap.

 

• a visual astro book like Turn Left at Orion or my own favourite, The Illustrated Guide to Astronomical Wonders is worth your time. Both explain what are some of the more important objects worth going for in a particular season. They'll explain how you get there (more or less assuming you're in a dark area, so if not, keep your wits about you). Both will explain how you move your finderscope (non-correct image for Turn Left, correct image for the Illustrated) to star-hop to the given DSO and both will offer a little 'positive' sketch of what the thing looks like in a normal 4" to 8" scope.

 

• if you can master patience you'll be a master of the night sky. To gain patience and to be concentrated and comfortable, a drummer's stool or an ironing chair is an absolute must. I truely belive being seated not only augments your concentration and patience but literally adds an inch or so to your aperture.

 

• there are little tricks you can learn to find yourself about the night sky. For example, find the plough in Ursa Major and look for Merek and Dubhe, the distance and angle between these two is one step. Now count that distance, in that direction another 5 steps and bingo, you'll be with the double star Polaris (do observe that!). Learning the big stars and diving quickly between them makes hunting stuff easier.

 

• cloudy nights are just that. Not wanting to go out is just that. Don't ever beat yourself up about not observing. This is a hobby and it is meant to be fun. Those stars and DSOs are not going anywhere quick. So, if you don't observe, no worries. Those gems of the night sky will be back to give you another chance tomorrow 😀

Edited November 20, 2019 by Rob Sellent