NGC 891 First Light

[The Thing]

Hi all, sorry about the clouds. I got a 'new' used scope from a Parisian with a holiday home and observatory on a hillside very close to Camembert. Not at all cheesy. I don't think he managed to collimate it as it is pretty much as new and he couldn't tell me much about how he'd used it. He's now got a C11 SCT.

Anyway I have collimated it and set it up. The only problem with this sort of scope is that the camera needs to be about 40cm behind the main tube! This accomplished with some hefty 90mm extension rings before the focuser (the weak point) and then a 15mm T-extension, the off-axis guider , filter drawer and camera. I nearly had to make some alterations to my laptop shelf but seem to have got away with it.

The advantage over a Schmidt-Cassegrain is there is no corrector plate on the front, so no lenses to cause aberrations and dew up. Also the mirrors seem to be much better made than cheap spherical SCT mirrors. They are parabolic and hyperbolic.

I need to try it with Jupiter and Saturn next.

Galaxy NGC 891
Information from catalog: ONGC
Magnitude: 10.84
Surface brightness: 24.17
Dimension: 13.0 x 3.0'
Position angle: 22
Radial velocity: 528
Class: Sb
Identifier: 2MASX J02223290+4220539,C 023,IRAS 02193+4207,MCG +07-05-046,PGC 009031,UGC 01831
Constellation: Andromeda


Lights 47x240s = 3h 8m, Gain 1600, Offset 30, Temp -5c
Image date, time and location: 2022-09-21, Manche, France
Telescope aperture and focal ratio: Teleskop Service Classic Cassegrain 8" f12 2436mm
Camera and filters used: QHY294PROC, Svbony UV/IR, OAG guided
Processing applied: PixInsight, Affinity Photo
This is uncropped.

[Carole]

That's a good result Duncan, both with the scope and the image. 

Don't worry about the clouds, I just bought myself a new scope too, a brand new one to replace my WO for a variety of reasons.  Not had a chance to test it out yet as only arrived yesterday, so waiting for the "new scope clouds" to disappear.

Won't fill your thread up talking about my new scope though. 

Carole
 

[The Thing]

Thanks Carole. I would like a really clear sky to test it out on, this image is a bit mushy due to intermittent murk going past and the guiding being a bit suspect.

Also the focuser is not very good,  I have already rebuilt it, it's a monorail design so not really suited for imaging, only one side of the focus tube is supported by a load of tiny ball bearings in grooves either side of the crayford track so there is not much hope of stability for imaging. I've just been reading up on tweaks for it. Might need to look for a replacement.

But the optics look like a huge improvement on my old 8" SCT

Have fun with your new scope!

Duncan

[Fay]

Fantastic Duncan, really nice......

[Roberto]

Very nice indeed Duncan!  I love this galaxy.  There's so much going on on its dust lane.  The colours, including field stars, are spot on.

Roberto

[The Thing]

Thanks Fay and Roberto. High praise indeed!

[MarkS]

Congratulations on the new scope. That's a great first result!

Mark

[The Thing]

Thanks Mark. I'm very pleased with it. Of course its been full moon and cloudy since I got this shot or there'd be more. C'est la vie.

I'm sure it'll produce better quality than this once I've fettled the GSO monorail focuser, I've already motorised it but it's a bit hit and miss autofocusing and this scope is temperature sensitive so focus needs regular tweaks during an imaging run.

And I've got a little monocular (as suggested on Cloudy Nights) on order to help with the collimation as it's hard to make out the concentric circle pattern on the mirrors which is very different to any other type of scope I have come across.