GSO RC testing review - Page 2

rat156 · #21 19-05-2009, 11:10 AM

Hope you get some clear skies Paul, looking forward to the results.

Cheers
Stuart

Alchemy (Clive) · #22 19-05-2009, 04:17 PM

Quote:

Originally Posted by rat156

Hope you get some clear skies Paul, looking forward to the results.

Cheers
Stuart

ditto

Paul Haese · #23 20-05-2009, 05:35 PM

Couple of images of what the set up looks like. I got everything balanced in both axis. Not sure about the vixen rings yet. I might get some flexure with this setup but time will tell.

Dennis · #24 20-05-2009, 06:12 PM

Hi Paul,

That’s a sweet looking set up! The photos clearly show the huge amount of back focus on this instrument.

Just one observation with the illustrative set up – the guide scope focuser assembly looks like a large cantilever. I’d be concerned with the guide camera cable hanging unsupported, unless you clamp it when in using the system vs. just demoing your set up?

Cheers

Dennis

gregbradley · #25 21-05-2009, 08:28 PM

Aren't those Losmandy gudie scope rings?

Be careful of the little lugs that stick out on the tightening knobs on the dovetail adapters as they break off easily.

Greg.

Paul Haese · #26 22-05-2009, 01:02 PM

Nope not Losmandy, they are ADM mate. I will be carefull though.

Terry B · #27 22-05-2009, 01:31 PM

Nice grey skies.

allan gould · #28 22-05-2009, 01:41 PM

Quote:

Originally Posted by Paul Haese

Couple of images of what the set up looks like. I got everything balanced in both axis. Not sure about the vixen rings yet. I might get some flexure with this setup but time will tell.

Thats a long imaging train Paul - I wonder why they made it soooo long?. Are they screw in connections or compression? Hope it all comes together for you.

Paul Haese · #29 22-05-2009, 01:58 PM

Allan, it pretty much all screws together. As I understand it, every RC has a long back focus length. If you would like to see some new images they are posted in the DSO imaging area. Pretty happy with this telescope. Cheap and half the price of large refractors.

gbeal · #30 22-05-2009, 02:18 PM

Quote:

Originally Posted by Paul Haese

Just a note on the Feather Touch. The construction of these focusors is superb, everything just fits like a glove and is very smooth too. The way the rollers and the guide bar are designed ensures that there is no flop at all. The brake seems very nicely made an would appear to hold a lot of weight. Easily as good as the Moonlite if not better. Lovely piece of engineering.

Preaching to the converted here. Did you get the digital motor unit as well?
Gary

Paul Haese · #31 22-05-2009, 05:19 PM

Just an update,

as most of you already will know, I managed to get some good imaging done last night with the OTA.

One thing that has cropped up several times is the problem with reflections. The image below shows reflections from last night's imaging run. Clearly there are stars outside the field that are influencing the field. I have seen it on Trevor's image of M83 too. This is of concern because galaxies should be the main criteria of this telescope.

I don't think it is the focusor (it is a new Feather Touch). I am also not convinced it is reflections from the Tak flattener.

So I am asking for advice and ideas where these things are coming from?

I tried several positions for the target. One showed one reflection, another showed 2 and this one shows 3.

leinad (Dan) · #32 22-05-2009, 05:27 PM

Yikes! Maybe contact Andrews Comms or GSO direct?
I was quite surprised that these scopes came with no collimation/user guide/instructions.

GL

gbeal · #33 22-05-2009, 05:47 PM

Yikes again, I thought you had circled the area with blue pen until I looked closely. Man alive they are serious. This is with a flattener? If so, try it without.
Gary

MrB (Simon) · #34 22-05-2009, 05:51 PM

Quote:

Originally Posted by gbeal

I thought you had circled the area with blue pen until I looked closely.

Ditto!

leinad (Dan) · #35 22-05-2009, 06:00 PM

Something in the focuser baffle tube ?

Paul Haese · #36 22-05-2009, 06:03 PM

Gary, I don't think it is the flattener. I noticed this when doing the star test when I first got the scope. If a bright star is just outside the field of view it seems to create this problem.

Other than that the scope produces lovely images.

MrB (Simon) · #37 23-05-2009, 03:29 PM

Just a though... is the inside of the CF OTA a not-so-nice glass finish resin like the nice polished outside?

TrevorW · #38 23-05-2009, 03:57 PM

No the inside is well baffled matt black however I believe reflections of this sort are not uncommon when imaging using SCT and RC's from what I have read.

I noticed them on the 10 minute exposures I took of M83 (not as bad as this) but not on the 6 minute subs I did of Centaurus A.

I'm fairly new to RC/SCT scopes and imaging in general but being so perfectly round could it be reflection caused in the baffle tubes.

Also refer this link may give some ideas

http://astro.umsystem.edu/apml/ARCHI.../msg00238.html

AlexN · #39 23-05-2009, 04:23 PM

I had the same sort of ring in my M83 images, and have noticed it also when centring bright stars for alignment... It happens when the bright star is just outside the cameras field of view... (very helpful when trying to centre a star for initial alignment of goto, however rather detrimental to final images..

MrB (Simon) · #40 23-05-2009, 04:51 PM

Someone needs to create a 'reverse' ray-trace program where you feed in an image with reflections, tell the software the image scale/FOV etc, plug in all the numbers/measurements of the optical system.. and it raytraces from the film plane back out to the aperature... sure would be a handy trouble-shooting tool!