Messier 42 with new MPCC

PhotonCollector (Paul) · #1 24-10-2005, 04:43 PM

Here's an image I did a few nights ago to try out my new Multi-Purpose Coma Corrector from Baader Planetarium. The weather hasn't been good at all, this image was taken in a clear spot between the clouds with the Moon rising.

The MPCC works a treat and it looks like it has removed the coma in my GSO 12-inch across the entire field ! It screws into my 2-inch eyepieces and also directly onto the front of the t-adapter for the Digital SLR.

The image of M42 is 4 exposures @ISO200 totalling about 9.3 minutes and covers about 49 x 33 arc-minutes.

The first image I attached in the natural looking image, the second image has an un-sharp mask to highlight certain details.

Here's a higher resolution version http://www.skylab.com.au/pmsa/ngc1976c.html
And the image which is un-sharp masked
http://www.skylab.com.au/pmsa/ngc1976d.html

Hope you like the images!

Paul M

ving (David) · #2 24-10-2005, 05:04 PM

nice shots paul. heaps of detail there.

i dont know if its my monitor or not but you seem to get heaps of red in the background sky?

PhotonCollector (Paul) · #3 24-10-2005, 07:38 PM

Quote:

Originally Posted by ving

nice shots paul. heaps of detail there.

i dont know if its my monitor or not but you seem to get heaps of red in the background sky?

Hi Ving,

No it's not your monitor - don't throw it away ;-). When I turn up the brightness on my monitor I can see a red glow down the right side of the image and the sky background has a brownish-red look.

The red glow down the right side is glow from the amplifier in the camera.

The sky backgound being reddish is probably my fault since the exposures are very short (about 2 minutes each @ iso200) that gives a poor signal to noise ratio (ie not enough signal, too much noise) and the background always appears noisy since it lacks density.

I haven't subtracted any dark or bias frames either. Also I probably pumped the red channel a little too much, and that didn't help either.

When the sky permits I'll do some deeper images of M42 and get more signal/density in the sky background.

Regards
Paul M

Itchy · #4 24-10-2005, 08:36 PM

Quote:

Originally Posted by PhotonCollector

The MPCC works a treat and it looks like it has removed the coma in my GSO 12-inch across the entire field ! It screws into my 2-inch eyepieces and also directly onto the front of the t-adapter for the Digital SLR.

Hi Paul

Nice test shots for the MPCC. I can't detect any coma at all. My MPCC arrived over a week ago and I can't get a clear night to try it out. Some people think that it will overcorrect on the SN scopes as there is already a corrector plate (although still considerable coma). I'll find out one of these nights!!!

Cheers

davidpretorius · #5 24-10-2005, 08:44 PM

nice, there are a few MPCC floating around now!

zipdrive (Dave) · #6 24-10-2005, 08:49 PM

great shot!!

where did you guys purchase your mpcc's from? i would love to get one..

Itchy · #7 24-10-2005, 08:49 PM

Quote:

Originally Posted by davidpretorius

there are a few MPCC floating around now!

What I find interesting is that no dealers in Australia seem to carry them (not that I could find). I had to get mine from the US.

Cheers

PhotonCollector (Paul) · #8 24-10-2005, 09:07 PM

Quote:

Originally Posted by Itchy

Hi Paul

Nice test shots for the MPCC. I can't detect any coma at all. My MPCC arrived over a week ago and I can't get a clear night to try it out. Some people think that it will overcorrect on the SN scopes as there is already a corrector plate (although still considerable coma). I'll find out one of these nights!!!

Cheers

Geeday mate,

yeah the MPCC is great. I know what you mean about the weather, I had to sneak out around midnight a few nights back when the skies partially cleared for a little while. But really the conditions were poor, the seeing terrible, but just enough clear sky to try out the coma corrector on M42.

As far as overcorrection is concerned: I would say you have nothing to worry about. The fact that your 'scope has a corrector plate is not an issue, your 'scope has coma and the MPCC corrects that - it wouldn't matter if your 'scope had a triplet-overhead-single-bypass lens or whatever - you 'scope produces coma at the film plane and the MPCC corrects the coma.

In fact another IIS member (tornado33) is using he's MPCC with a f/3.6 Schmidt-Newtonian and he's over the moon, since it always produced a fair bit of coma and now it's all but gone!

Baader say that the MPCC is designed for f/4 to f/6 telescopes and works best when the MPCC is placed 55mm from ccd plane. It turns out mine is 54mm, so I might fittle to add 1 mm.

What f/ratio is your 'scope ?

Paul M

PhotonCollector (Paul) · #9 24-10-2005, 09:22 PM

Quote:

Originally Posted by zipdrive

great shot!!

where did you guys purchase your mpcc's from? i would love to get one..

Hi Zip Drive,

Talk to Bob Luffel alpineastro@alpineastro.com at Alpine Astro (www.alpineastro.com). I ordered and had the MPCC a week later.

Here's the link for the MPCC http://www.alpineastro.com/optical_a...ories.htm#MPCC

Tell Bob, that Paul M. said "how about a discount for all us IceInSpace purchasers?"

:-)

Paul M

Itchy · #10 24-10-2005, 09:29 PM

Quote:

Originally Posted by PhotonCollector

Geeday mate,

As far as overcorrection is concerned: I would say you have nothing to worry about. The fact that your 'scope has a corrector plate is not an issue, your 'scope has coma and the MPCC corrects that - it wouldn't matter if your 'scope had a triplet-overhead-single-bypass lens or whatever - you 'scope produces coma at the film plane and the MPCC corrects the coma.

That's what I think too, but these guys on the LXD group want to see the proof, so hopefully I can give it to them soon.

Quote:

In fact another IIS member (tornado33) is using he's MPCC with a f/3.6 Schmidt-Newtonian and he's over the moon, since it always produced a fair bit of coma and now it's all but gone!

Baader say that the MPCC is designed for f/4 to f/6 telescopes and works best when the MPCC is placed 55mm from ccd plane. It turns out mine is 54mm, so I might fittle to add 1 mm.

What f/ratio is your 'scope ?

OK, my SN10 is f4. Meade says that the corrector plate gives the scope the coma of an f6. So the MPCC should do the job very nicely.

Cheers

ving (David) · #11 25-10-2005, 12:51 PM

oh and paul, thats a lovely looking setup you have there

tornado33 · #12 25-10-2005, 02:12 PM

Howdy all
I have yet to star test the MPCC on the 6 inch F3.6 s/n but am keen to do so, from the daytime shots it should get rid of most of the coma

I expected it to get rid of most of the coma from the 10 inch F5.6 but it seems to have got rid of every bit of it

Scott