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Second Scope - Astrophotography


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H Folks

I have a 5 inch Celestron Matsukov  Cassegrain  - which is good but is giving me alignment problems. I want to next buy a Equatorial mount telescope - maybe a 10 inch F/3.9 of F/4.8 reflector. I hope to do some simple Astrophotography.

My question is which is a good 10 inch reflector with a GEM in around $1000.

Should I buy a mount and OTA separately or as a package unit. 

Is it necessary to buy a GEM with motors or can they be purchased later. 

Maybe I could use my existing MAK with the new GEM as well. What should I keep in mind for this

regards

Rajeev

 

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I would not recommend a 10"/250mm Newtonian reflector if you're starting out in astrophotography. Remember that with photographic imaging you can accumulate light, as opposed to visual observing where what you see is what you get - so aperture is in many respects less important.  Perhaps the most important factor in imaging is the mount which needs to be very stable and have very precise tracking. The bigger and heavier the telescope, the more expensive your mount will be. For a suitable mount on this size of telescope, plan to spend well over $1,000 on just the mount.

Personally I would rethink your expectations and needs. Different makes and models will be available in the US, what the local offer is in Jamaica I have absolutely no idea! But think of something like the Skywatcher EQ3 goto mount as the minimum for astrophotography with a small and light telescope - in the UK this will cost new about 400 pounds. https://www.firstlightoptics.com/skywatcher-mounts/skywatcher-eq3-pro-synscan-goto.html

Moving up to the EQ5 which has much sturdier steel legs versus aluminium, will be a significant improvement - but the cost goes up (about 550 pounds in the UK). A step above this is the HEQ5 at about 780 pounds new - you really will need something at least like this to support a large telescope, and even then I reckon about a 200mm reflector is on the limit.

Perhaps the least expensive telescope to start in astrophotography would be the Skywatcher 130 P-DS which is a 130mm aperture refector modified for imaging. Cost in the UK about 175 pounds. https://www.firstlightoptics.com/reflectors/skywatcher-explorer-130p-ds-ota.html  There's also a larger version with 150mm aperture. https://www.firstlightoptics.com/reflectors/skywatcher-explorer-150p-ds-ota.html

Very popular for imaging are smallish refractor telescopes in the 80mm or 90mm aperture range. Apochromatic are the best, but expensive. Semi-apo aren't cheap, but considerably more reasonable.

To add to the cost, you will probably want to consider corrector lenses depending on the type of telescope, and eventually a guidescope set up. However, the first priority should be a good mount.

Your Mak will be totally usable with any mount provided the Dovetail bar is compatible. Basically there are two types: Celestron/Vixen or Losmandy, so check. Some mounts will take both, otherwise you will need to change the dovetail - but usually this is not a problem.

 

 

 

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Astrophotography is a bit "strange" in that it does not follow the thinking for visual.

For visual you basically think of a bigger scope to see more, in AP the move is usually the other way, you want a small scope (fast in photographic terms). As said Visual is big scope and small mount, AP is small scope and big mount.

Depending on the available mounts I would say (if sensible) keep the 5" and get a nice Equitorial goto and add an imaging scope to that and so have the Mak for visual and the other for AP. You are likely looking at about the level of the HEQ5 here, which I guess means the iOptron CEM25 or whatever Orion mount. These tend to be the most common selection.

A 10" f/4 would I suggest be a nightmare to use unless set up permanently in a semi-professional observatiory, and even then a lot of time would be required to set and set it up almost at every occasion it is used. I could not suggest an EQ mount capable of handling one easily either. Me bank balance just would not reach that far sop never crodded mu mind to look.

Packages tend to be aim at the visual side, not the AP side. They may say "Can attach a DSLR " but it is more along the lines of "You can attach a DSLR with super glue or a 6" nail" It is "attached" but not necessarly much good.

About the simplest yet reasonable set up at the lower cost end was an EQ5 goto with a 72mm William Optics ED refractor. Produced good images and reasonably low cost. The "disadvantage" being that if you decided to put say an 80mm triplet on or add guiding then the mount needs upgrading. Having said that an off axis guider+camera may not add too much weight, especially if any DSLR was dumped and a cmos/ccd used instead. But it is limited. So depends on the extent to which you want to go, at least initially.

Having seen this (several times) and the results to cost comparison it is certainly worth thinking of.

I suggest you get the goto as eventually you will want it - better motors, less time finding things, interface for guiding.

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Nothing simple about a 10" reflecting imaging rig. It is enormous and while it can deliver, it will require an immense number of factors to be spot on to really work well. For the budget stated, I would think significantly smaller in terms of kit, but as mentioned, this does not mean smaller in ambition. The best images I have taken have been from my smallest kit.

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Just take a look at some of Olly and Sara's images, very many of which are taken with relatively small refractors.  However, a decent quality refractor and FF could eat up your whole budget easily.

Why not invest it all in a decent mount and keep your Mak?  Do you feel that the Mak is the cause of your alignment issues?  If not and you get a good GEM mount, the Mak is a reasonable all rounder until budgets become available to upgrade that.

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Dear All

Thanks for your replies. What I gather from all of you is that I should

- start with a good GEM go to mount (and use the 5" MAK with it - both for visual and photography)
- next upgrade to either a 4" refractor (for photography with above GEM go to mount) or a 8-10" reflector with a simple mount (for visual observation). I can decide this later.

Assuming that I will now purchase a good GEM go to mount, which one should I look at which can handle the MAK and photography (and later a 4" refractor for photography). I would like the budget to be within $1000.
Why are mounts so expensive !

thanks, Rajeev

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Just in case I buy an OTA first - before the mount. How would the Sky-Watcher ProED 100mm f/9 Doublet APO Refractor be, both for visual and astrophotography.

Also, I reckon it is light enough to be used with my 5" MAK Alt Az computerized mount? Correct?

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