Jump to content

NLCbanner2024.jpg.2478be509670e60c2d6efd04834b8b47.jpg

Widefield Triple Imaging Rig

Gina

By Gina
in DIY Astronomer

Recommended Posts

  • Replies 351
  • Created
  • Last Reply
Gina

Gina

Posted
  • Author
Posted

Thanks Mark :) These were taken with vintage SLR lenses from the film days. Astrodon filters.

  1. Ha with Hannimar 135mm f2.8 at full aperture and 5nm filter with Atik 460EX mono CCD camera.
  2. OIII with SMC Takumar 105mm f2.8 lens at f4 and 3nm filter with Atik 314L+ mono CCD camera.
  3. SII with SMC Takumar 105mm f2.8 at f4 and 5nm filter with another 314L+
Link to comment
Share on other sites
Gina

Gina

Posted
  • Author
Posted

The guiding wasn't perfect last night but I don't know why it showed more in the OIII image - all three were taken at the same time except that I rejected some subs due to passing cloud. I'll go through the OIII subs again and just check that I didn't include a bad one by mistake.

Link to comment
Share on other sites
Naemeth

Naemeth

Posted
Posted

The guiding wasn't perfect last night but I don't know why it showed more in the OIII image - all three were taken at the same time except that I rejected some subs due to passing cloud. I'll go through the OIII subs again and just check that I didn't include a bad one by mistake.

I think it's there in the other two as well :(. I could only notice it zooming in to maximum on the other two though.

Link to comment
Share on other sites
Gina

Gina

Posted
  • Author
Posted

Yes, the guiding deteriorated as time went on last night - I think the mist gradually came in affecting the wideband guiding more than the narrowband imaging (maybe an Ha filter might improve it). Anyway, I've gone through th 11 OIII subs and zoomed in on each one and 2 were definitely worse. So I removed those and restacked the remaining 9. Then stretched that and this is the result.

post-13131-0-84068700-1377600758_thumb.p

Link to comment
Share on other sites
Naemeth

Naemeth

Posted
Posted

Yes, the guiding deteriorated as time went on last night - I think the mist gradually came in affecting the wideband guiding more than the narrowband imaging (maybe an Ha filter might improve it). Anyway, I've gone through th 11 OIII subs and zoomed in on each one and 2 were definitely worse. So I removed those and restacked the remaining 9. Then stretched that and this is the result.

post-13131-0-84068700-1377600758_thumb.p

Certainly an improvement without those 2 subs :).

Link to comment
Share on other sites
sloz1664

sloz1664

Posted
Posted

Hi Gina,

The Triple rig is coming on a treat, I think you are onto a winner there.

All those hours of subs in one hit.

Just a thought, when you have proved you're complied arduino code for the triple focuser,

would you mind if I posted it in the arduino projects folder of the sgl observatory automation yahoo site, obviously

the compilation would be accredited to yourself. Unless you're member yourself, that is :icon_biggrin:

cheers

Steve

Link to comment
Share on other sites
Gina

Gina

Posted
  • Author
Posted

Yes, the guiding deteriorated as time went on last night - I think the mist gradually came in affecting the wideband guiding more than the narrowband imaging (maybe an Ha filter might improve it). Anyway, I've gone through th 11 OIII subs and zoomed in on each one and 2 were definitely worse. So I removed those and restacked the remaining 9. Then stretched that and this is the result.

post-13131-0-84068700-1377600758_thumb.p

Link to comment
Share on other sites
Gina

Gina

Posted
  • Author
Posted

Hi Gina,

The Triple rig is coming on a treat, I think you are onto a winner there.

All those hours of subs in one hit.

Just a thought, when you have proved you're complied arduino code for the triple focuser,

would you mind if I posted it in the arduino projects folder of the sgl observatory automation yahoo site, obviously

the compilation would be accredited to yourself. Unless you're member yourself, that is :icon_biggrin:

cheers

Steve

Thank you Steve :)

I'm quite happy for you to post the Arduino code wherever you like. Once anything is posted in these forums it goes into the Public Domain anyway :) I've tried to join that Yahoo group but there is some obscure problem with Yahoo. I'm a Yahoo member and a member of several groups and can access those with no problem at all but when I try to join a new group it doesn't recognise me :( Weird of what?!

Link to comment
Share on other sites
Gina

Gina

Posted
  • Author
Posted

Clear sky again last night so I went to the Heart Nebula and slewed over to the Soul. I worked out that if I turned the cameras 90 degrees I should be able to get both Heart and Soul Nebulae in the frame. When I tried it looked like the alignment was out and wasn't sure I could get all of both nebulae in all three frames at the same time. So I went back to plan A - mosaic of Heart & Soul, and I put the Soul Nebula in the middle of the frame and set everything up as for the Heart the previous night.

Link to comment
Share on other sites
Gina

Gina

Posted
  • Author
Posted

I've found the problem with the OIII - the aperture had moved and it was half a stop more open than f4. Previous experience showed that f4 was the maximum aperture before star bloating occurred. Maybe I should go half a stop smaller to be more sure of avoiding star bloat even though it means longer exposures.

I have now turned the cameras through 90 degrees and re-aligned the images. So next time we get a few hours of clear sky I can set up to get both Heart and Soul in the frame. I think the exposure for OIII and SII wants increasing to an hour.

Link to comment
Share on other sites
Gina

Gina

Posted
  • Author
Posted

The sky cleared (at least for a while) and I had the Heart & Soul nicely framed and running 20m Ha, 30m OIII and 30m SII. The forecast was for bits of cloud so I didn't think longer subs would be a good idea. Guiding was fine for an hour or so then packed up.

Here are single subs of Ha, OIII and SII stretched in Ps.

Oh dear, got upload trouble :(

Link to comment
Share on other sites
Gina

Gina

Posted
  • Author
Posted

And here's the three channels combined with histograms adjusted to match. This is the full frame and shows the alignment between channels. The OIII is just a tiny bit out but good enough for most objects, I think. The result of rotating cameras shows a shift of alignment and that alignment will need adjusting if camera orientation is changed. I was hoping that once set, the alignment could be fixed but it seems I will want alignment to be adjustable. Some form of very fine control required - threaded rod or maybe little cams.

post-13131-0-18496500-1377851991_thumb.p

Link to comment
Share on other sites
Gina

Gina

Posted
  • Author
Posted

Clear sky tonight so imaging Heart & Soul again. Ha with 20m subs but tried OIII and SII with 30m subs and they're very poor so I've now upped those to 1 hour subs. Here's the first subs of Ha 20m - OIII 30m - SII 30m

post-13131-0-44323700-1377986393_thumb.p post-13131-0-76221200-1377986425_thumb.p post-13131-0-99198700-1377986457_thumb.p

Link to comment
Share on other sites
Gina

Gina

Posted
  • Author
Posted

The clear sky last night lasted until dawn and I was able to get over 8 hours of imaging time. First subs showed poor OIII and SII so I decided to increase the time to an hour and hope for the best. That lost me some time on those but I managed to get 27 x 20m Ha and 7 x 60m OIII and SII. So that's a grand total of 23 hours imaging time last night :) Only trouble was that the guiding was not quite up to the hour long subs and I shall need to do better on that. I want to get AA5 running for guiding as I'm told that is a lot better than PHD. There are other things to try too such as reducing the aperture further on the guide lens and maybe defocussing a bit more. I'm using 2s integration time and it may be better to reduce the image brightness and increase that. I'm using a 200mm lens at f8 ATM and SX Lodestar with PHD.

Link to comment
Share on other sites
Gina

Gina

Posted
  • Author
Posted

Clear skies tonight and now imaging IC1396 which contains the Elephant's Trunk. Took a while to get going as I had PHD problems - OK now though :)

post-13131-0-96613100-1378158746_thumb.p

Did a couple of 10m subs as exposure test and decided on same as for Heart and Soul viz. 20m Ha and 60m OIII and SII.

Just finished the first 20m Ha.

post-13131-0-69741000-1378159118_thumb.p

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

Go to topic listing

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.