Newt upgrade

[graham.hobart]

I'm thinking of selling my 8" SW Quattro f4 newt to get it's bigger brethren the 10" f4 as I like it so much.
I also am considering upgrading the MPCC coma corrector I have to a Paracorr Type II (2 inch)
I am looking for expertise from those who have similar to point out any issues. I aim to use my cooled DSLR or QHY 8 colour cameras in it as I find little time now for LRGB.
Having never used a Paracorr what is the connection issues with it and EOS or T2 type? The schematics mention a standard TV connector- is this the only way? is it expensive ?
(I am not overly fussed by back focus issues as I will still using a guide scope I think) . I think the Paracorr is constrained anyway to 55mm BF?
Cheers all
Graz:D

[rustigsmed]

Hi Graz,


FOR IMAGING APPLICATIONS
1) Back off set screw under flange (D) so you can unscrew lens assembly.
2) For use with DSLR cameras (APS size chips recommended, as full-size chips will show vignetting). Tele Vue Canon Wide-T Adapter CWT-2070, or Standard T-Ring Adapter TRG-1072 attaches directly to the Paracorr Type-2 flange.
3) For CCD cameras, use Tele Vue Imaging System accessory tubes with Tele Vue camera adapters, or A2A-1107 adapter for cameras with 2" nosepieces. Best back focus is approximately 55mm from flange face.
http://www.televue.com/pdf/literature/Pacacorr%20Type-2%20Instructions.pdf

https://www.optcorp.com/tele-vue-t-ring-adapter-is-to-t-ring.html

It is 55mm.

I'd consider going something with my BF in case you decide on going OAG down the track.

All the best,

Russ

[graham.hobart]

cheers Russell!
Have you ever used one? If so is it way better than the MPcc?

[rustigsmed]

hi graham,

I have only used a friend's one for visual - and that was some time ago. they are of course good, I'm not sure if I'd say they are way better than the MPCC.
They are designed to go down to F3 I think while the mpcc is f3.5 and up. The have a 2xdoublet lens design and I think the mpcc is a triplet.

at f4 I'm not sure it's worth the extra $ for having the same BF and not using a scope closer to the f/3ish limitations.

there are other options out there too worth looking into if you were certain on changing from the MPCC such as:
http://www.teleskop-express.de/shop/product_info.php/info/p5836_GPU-Aplanatic-Koma-Korrector-4-element-fuer-Newton-Teleskope-ab-f-4.html

http://www.teleskop-express.de/shop/product_info.php/language/en/info/p5090_ASA-2--Newton-Koma-Korrektor-Quattro---1-175-fach.html

Or the baader Rowe. the MPCC is a great little performer for the price as you know but I think when using at f4, personally I would put the $ into a focuser or OAG (although then you might need one with more BF).

Don't let me dissuade you though, others may think it is well worth the money.

Best of luck

Russ

[graham.hobart]

Good advice there, I will ponder further.
I have a Starlight xpress thin OAG on my SX filter wheel. Would be great if I could fit that in somewhere in the train as it is tiny. Needs the screw holes on the filterwheel though I think. Really can't see me spending more time in the future with the filter wheel, LRGB is just too time heavy for me currently.

[garymck]

Hi,
I also have an 8" Quattro.

Please be aware that the coma corrector here:
http://www.teleskop-express.de/shop/product_info.php/info/p5836_GPU-Aplanatic-Koma-Korrector-4-element-fuer-Newton-Teleskope-ab-f-4.html

Is also sold by Skywatcher and is available at Astro Pete's in Brisbane for $349 - way cheaper than getting it from Germany.

I have found it is perfectly corrected to the edge of an APSC chip - may go bigger but I don't know as I don't have a chip any bigger.

The caveat is that collimation MUST be bang on with ANY of the longish coma correctors. If you are even a little off the stars will be out in one corner.

I had to remove sag from my Quattro focuser (these steel tracks are nowhere near as good as a Moonlight), round the ends of the collimation screws, put a steel washer between the screws and the secondary holder and put stronger springs in the primary cell.

I did NOT have to do that when I used an MPCC - this is much more tolerant of any collimation error.

The results to my eyes are no better than the MPCC. If I'd known what I know now, I would have stuck with the MPCC......

I also wouldn't bother going to the 10 inch - all you get is a slightly greater image scale.................not significantly so anyway.....

FWIW
Gary