equipment nirvana

[Peter.M]

As a beginner to astrophotography using a newtonian I thought I would share my experiences with gear. For a start I am using a GSO f4 rolled steel tube newtonian mounted on a heq5 pro. Currently I am autoguiding with a ssag and a 50mm guidescope.

To get this system to work with my existing dslr I required a coma corrector (baader MPCC) and some sort of collimation tools. Acting on the advice of Brendan Mitchell I purchased a full set of cats eye tools. A few days ago I picked up a light box from Exfso for flat frames.

I have since changed my dslr for a qhy9 mono, and what I belive to be the last items I need to get the system singing are on the way.

I have a 2.5 inch moonlite focuser with a threaded drawtube in the mail, and from Germany a 2.5 inch OAG (Telescope service). I plan to attach the OAG straight to the focuser via threads. To do this I will require slightly more backfocus than I currently have so I will need to move the primary mirror closer to the secondary.

I guess the point of my post is for anyone deciding on a telescope to buy for astrophotography is that while that cheap newtonian seems like a bargain there are modifications required to adapt it to your requirements. I would still recomend a newtonian for astrophotography but be prapared to tinker.

[Mark_Heli (Mark)]

Hi Peter,

This is a really great post. There is lots of experience that goes into selecting the right equipment that works togther as a system and sharing the knowledge will benefit many other members looking to get setup.

Once eveything is setup, it would also be great to see a series of images which shows the quality of pictures taken at different stages of equipment evolution.

Cheers,
Mark

[Visionoz (Bill)]

Peter

I've noted your comment in your earlier post about the TS 2.5" OAG

I've got one of those and it works for both my 80mm & 120mm refractors on a MoonLite focusers - however I would have thought that this model is what you would actually need in your case for the f/4 newt - http://www.teleskop-express.de/shop/...elescopes.html

BTW Patrick should have advised you with the correct model for your usage - it would be interesting if you could actually use the TS 2.5" OAG with the newt - would love to see your assessment after you've worked out how everything fits - because then I would save heaps by using mine for my 12" newt without having to resort to the other model which I highlighted in the preceding paragraph

Cheers
Bill

[Peter.M]

The OAG that you linked looks interesting indeed. I did not advise what telescope that I would be using when I ordered so it is already in the mail. I suspect that using my Qhy9 with this and a SSAG would cause problems with the OAG being so close to the filter wheel. It would only work in one position. I went with the 2.5 inch OAG to put it in front of my current corrector.

At the moment the camera comes into focus around 10 mm to close to the focuser to fit the OAG before the corrector, so what im going to do is move the mirror up the tube a bit. It should work fine as the larger apeture focuser secondary and OAG should accomodate the light cone.

I will let you know how I go, and no doubt post some images. Most of all im looking forward to having no problems with differential flexture!

[Visionoz (Bill)]

Thanks Peter for the feedback!

Well I hope that you'd not have to move the primary mirror too much up but from my own use of the low-profile MoonLite focuser that I have for my 12" newt - it would be more likelihood that you'd need to move it up quite a bit but I'm sure you're prepared for it anyway

The TS 2.5" OAG is quite hefty indeed and is at least 31mm thick optically (from front-to-rear flange) and as you know with most refractors there's lots of back-focus so I had no problems to gain focus with the main CCD camera and the guider CCD for both my 80mm & 120mm OTAs BUT I had to fiddle around alot (in fact I had to cut the 1.25" nosepiece shorter) before I could get focus with the Orion SSAG that I was using - I however could not use the OAG with my VC200L with the FR as the back-focus distance was just too short @ aro 88mm! And I've still yet to try the 10"RC!!

However the results are very good and I've since improved my lot by using a StarlightXpress Lodestar instead and immediately I've got literally about 100 times more stars visible in PHD when compared to the SSAG - this is because "that very expensive" Lodestar is much more sensitive than the SSAG!

One point that you'll note is that sometimes the stars are longish-shaped like bananas (Brendan will confirm this - in fact the word "bananas" is his! ) and yet PHD will guide perfectly on them!! I noticed that with the Lodestar I've lost the "bananas" and now've got round stars to guide on though !

It's a shame that you didn't realise that there were other models of the OAG available - in fact I was thinking of ordering tonite that one I showed you but when I saw your post I'm holding off till I see your results - otherwise it'll have to be very appropriate as per the title of your thread - ie Equipment Nirvana!! - yep, it never ends does it? Spenda the monee!

Looking forward to good news from your exercise in this Good luck!

Cheers
Bill

[Peter.M]

I recieved and fitted the moonlite focuser yesterday, boy it is a nice unit. Today I got the TS OAG, it is also solidly made and looks like it will work a treat. Problem is it is a 69mm thread telescope side and my focuser is a 68mm thread, I now have to wait for a custom adaptor to come from the states.

[bmitchell82 (Brendan)]

you fellas got it easy , i had to figure all that information out pretty much on my own But alass i have no problem in helping another poor lost soul in Nirvana

Im currently peeling off 15min Ha on the HH utilizing my OAG FT and a EQ6 all be it with a 10" F4.7 instead, even with a tiny bit of breeze its holding nicely. Lets hope

Look forward to all the pieces coming together Peter and you produce some cracker shots.!

Brendan

[Visionoz (Bill)]

Originally Posted by bmitchell82

... But alass i have no problem in helping another poor lost soul in Nirvana ...
Brendan

Yep - "poor lost soul" indeed and I'd thought it was you that was lost when you left for the airport and I heard later the news on the radio! Haven't heard a pip-squeak outta 'ya since my last SMS!

Never mind - at least I now know that the tropical cyclone missed picking 'ya up on your hols up north - hope you had a good time with family & friends over the festive season!

Cheers
Bill