Imaging with the 130pds

[mAnKiNd]

On 17/04/2017 at 14:38, wimvb said:

@mAnKiNd:

Here's a pic with the focus settings of my scope/cc/camera.

The line marked K20D is for just the camera. The line below is for camera with Baader CC.

Dear Wim, thanks again for sharing that photo.

Would it be possible for you (or anyone else willing for that matter), to measure the total length of the drawtube in the 130PDS focuser from point of contact at the top locking ring to the end inside the OTA?

This is because the coma corrector I just ordered is approximately 10cm in length and it would be good to know if it will sit inside or outside the drawtube before it arrives.

Many thanks again.

Edited April 19, 2017 by mAnKiNd

[alacant]

48 minutes ago, mAnKiNd said:

Even closer to my distance..

You need an eos to m48 adaptor. If you can find one with 10mm thickness, that gives you 54mm; no room for a filter other than on the end of the cc. If you're going it alone, the best place to start would be with this  giving 45mm, leaving you to find the impossible; an 8mm m48 spacer. Or, just leave the problem with TS. They'll send you what you need;) HTH.

[mAnKiNd]

37 minutes ago, alacant said:

You need an eos to m48 adaptor. If you can find one with 10mm thickness, that gives you 54mm; no room for a filter other than on the end of the cc. If you're going it alone, the best place to start would be with this  giving 45mm, leaving you to find the impossible; an 8mm m48 spacer. Or, just leave the problem with TS. They'll send you what you need;) HTH.

Thank you for your reply. Ah yes, I failed to mention that my filter is a clip-on, meaning it sits inside the camera. Otherwise, you are correct in saying that there would be no room for a filter. Therefore, with my current setup, I should have a 52.8 mm spacing between lens and sensor. The Baader EOS locking ring has an M48 thread. Thanks again

 

[richyrich_one]

1 hour ago, mAnKiNd said:

Thanks again for sharing this really useful information.

If you consider the focal flange distance of a Canon is 44mm, plus the 11mm from the Baader EOS locking ring I'm using, then that gives me 55mm total distance from lens to sensor.

However, since I use a IDAS LPS-D1 filter, which has a glass thickness of 2.2mm, then if I understand correctly, I can subtract that value from the total distance, giving me a "true" distance of 52.8mm, which is not a far cry from the recommended 52.5mm.

Considering the slight differences in each item due to manufacturing tolerances, I might just turn out lucky and that extra 0.3mm turns out fine, if anything, it might not even produce a significant difference between 52.8mm and 52.5mm.

The proof will be in the pudding though..soon

EDIT: looking at the graph you shared one more time, it looks like for 650mm focal length, it is around 52.6mm! Even closer to my distance..

For filters you allow 1/3 of the glass thickness. So for your 2.2mm filter you can allow about 0.7mm.

[mAnKiNd]

7 minutes ago, richyrich_one said:

For filters you allow 1/3 of the glass thickness. So for your 2.2mm filter you can allow about 0.7mm.

Ah, thank you for the correction. That translates to 54.3mm, which is 1.8mm more than the 52.5mm recommended. This changes things a little as now i need to get one of those thin EOS locking rings (thanks alacant) and build up the distance with spacers. Thank you again for pointing this out ?

Edited April 19, 2017 by mAnKiNd

[Atreta]

I'm feeling completly dirheartebed about getting my 130pds out.   Tried everything on the book to get a good polar alignment,  sharpcap polar alignment to alnost 0:00:00, phd2 drift alignment keeps bouncing up and down,  the synscan polar alignment utility.  Also tried darv method,  one star drift and so on. 

With my 135mm lens i can get up to 2 or 3 minutes unguided.

I don't know what else to do,  yesterday i wasted a whole night trying to use and came back with nothing. 

What could it be?  I'm feeling like i'm the dumbest astrophotographer ever. 

 

[wimvb]

2 minutes ago, Atreta said:

I'm feeling completly dirheartebed about getting my 130pds out.   Tried everything on the book to get a good polar alignment,  sharpcap polar alignment to alnost 0:00:00, phd2 drift alignment keeps bouncing up and down,  the synscan polar alignment utility.  Also tried darv method,  one star drift and so on. 

With my 135mm lens i can get up to 2 or 3 minutes unguided.

I don't know what else to do,  yesterday i wasted a whole night trying to use and came back with nothing. 

What could it be?  I'm feeling like i'm the dumbest astrophotographer ever. 

 

I know the feeling. Some time ago, I had a similar experience. I couldn't get polar alignment right, no matter what I did. Finally it dawned on my that I was stepping around on the soggy grass after winter, and my telescope actually bounced up and down every time I passed too close to the north leg of the tripod. This despite it being on fence-post-anchors that are driven into the ground. Sometimes it's those small annoying things that ruin a session, untill you figure out what it is. In the end, I gave up on trying to get polar alignment perfect and just went with it. Guiding was good and the images turned out ok anyway.

I'm sure that if you come back another night, everything will run smoothly.

[Atreta]

4 minutes ago, wimvb said:

I know the feeling. Some time ago, I had a similar experience. I couldn't get polar alignment right, no matter what I did. Finally it dawned on my that I was stepping around on the soggy grass after winter, and my telescope actually bounced up and down every time I passed too close to the north leg of the tripod. This despite it being on fence-post-anchors that are driven into the ground. Sometimes it's those small annoying things that ruin a session, untill you figure out what it is. In the end, I gave up on trying to get polar alignment perfect and just went with it. Guiding was good and the images turned out ok anyway.

I'm sure that if you come back another night, everything will run smoothly.

Thanks,  Wim

Problem is my guiding never worked the way it should.  It goes ok for a few seconds and then everything goes crazy.  The next thing i'm thinking of trying is to use an eqdir cable to help with it and send my mount to somebody try it. 

[wimvb]

Good luck, hope you get it sorted out.

[Atreta]

Thanks,  gonna post here when i do it

[Thalestris24]

Hi Frank

It sounds to me like PA isn't your root problem. After all, PA errors will only cause field rotation. I'd look at things like balance and flex. Not sure what guide scope and camera you're using? You maybe need to look at how your setup performs unguided whilst running the PHD2 Guiding Assistant - that can tell you a lot about where problems may lie. Perhaps you can post your PHD2 settings and PHDlog analysis? How is your PHD2 calibration? Also, when you say 'everything goes crazy' can you be more specific?

Louise

[Thalestris24]

15 hours ago, Thalestris24 said:

Hi Frank

It sounds to me like PA isn't your root problem. After all, PA errors will only cause field rotation. I'd look at things like balance and flex. Not sure what guide scope and camera you're using? You maybe need to look at how your setup performs unguided whilst running the PHD2 Guiding Assistant - that can tell you a lot about where problems may lie. Perhaps you can post your PHD2 settings and PHDlog analysis? How is your PHD2 calibration? Also, when you say 'everything goes crazy' can you be more specific?

Louise

ps be aware that if you happen to be guiding with a qhy5l-ii in ST4 mode then your guide cam must be set to 8 bit rather than 12 otherwise it won't work!

Louise

[Atreta]

1 hour ago, Thalestris24 said:

ps be aware that if you happen to be guiding with a qhy5l-ii in ST4 mode then your guide cam must be set to 8 bit rather than 12 otherwise it won't work!

Louise

Hi Louise,

i'm using an asi120mc with an orion 50mm finderscope. does the asi120mc have to be at 8bit too?

here is my logs from the previous night, there are some crazy graphs because i forgot to turn guiding off while i tried to do a new darv alignment.

PHD2_GuideLog_2017-04-22_005622.txt

the one below is when i tried to guide with only the t5i.

PHD2_GuideLog_2017-04-22_005622.txt

thank you for all the help

PHD2_GuideLog_2017-04-16_193117.txt

[Thalestris24]

56 minutes ago, Atreta said:

Hi Louise,

i'm using an asi120mc with an orion 50mm finderscope. does the asi120mc have to be at 8bit too?

here is my logs from the previous night, there are some crazy graphs because i forgot to turn guiding off while i tried to do a new darv alignment.

PHD2_GuideLog_2017-04-22_005622.txt

the one below is when i tried to guide with only the t5i.

PHD2_GuideLog_2017-04-22_005622.txt

thank you for all the help

PHD2_GuideLog_2017-04-16_193117.txt

Hi

Yeah, I think the asi also needs to be set to 8-bit for ST4 operation. You need to put your logs into PHDLab so that you can see what's going on.

Louise

[wimvb]

Frank, have you tried running the PHD guiding assistent (under the Tools menu)? It will report the status of your setup. If there is backlash or the settings are off, the assistent will suggest what to do.

[Atreta]

7 minutes ago, Thalestris24 said:

Hi

Yeah, I think the asi also needs to be set to 8-bit for ST4 operation. You need to put your logs into PHDLab so that you can see what's going on.

Louise

I'll give it a try tonight if the skies allow it and get a cleaner log file too.

thank you.

7 minutes ago, wimvb said:

Frank, have you tried running the PHD guiding assistent (under the Tools menu)? It will report the status of your setup. If there is backlash or the settings are off, the assistent will suggest what to do.

Wim, yes i did, yesterday i tried and the polar alignment error was bouncing from 0.4 to about 10 or more, backlash i don't recall the value but it displayed some backlash too.

if i'm able to run it tonight i'll grab some screenshots and post here.

thank you

[spillage]

18 hours ago, Atreta said:

Wim, yes i did, yesterday i tried and the polar alignment error was bouncing from 0.4 to about 10 or more, backlash i don't recall the value but it displayed some backlash too.

I can only add that you us a eqdir and allow phd to drift align until the graph starts moving along. I find that until the graph starts moving my pa will not settle down.

[Atreta]

17 hours ago, spillage said:

I can only add that you us a eqdir and allow phd to drift align until the graph starts moving along. I find that until the graph starts moving my pa will not settle down.

I got to connect my mount with eqmod through pc direct mode,  tested everything indoors because the sky was all cloudy.  I did a lot of research and decided to give the pc direct a try since i don't have the eqdir cable and if this works nicely i may make one eqdir cable myself or import one from shoestring.  Lets hope the skies clear soon

Thanks. 

[Atreta]

Great news, got to test it out tonight, did some play with eqmod and stellarium to get my way around it, then  ran phd2 drift alignment and did a rough azimuth adjustment, didn't bother with altitude adjustments this time.

guiding was a lot better and i did a single 5 minutes test shot. here it is:

m8 - lagoon nebula 1x300s iso 400

Besides the huge coma, is this ok for a 5 minutes sub? Let's hope it's not just beginners luck 

thanks a lot for all the help so far,  sure i'm gonna need more.

 

 

 

[wimvb]

That looks great! Glad you sorted out the problem. With a coma corrector (I use a baader on my 150pds), stars will look much better too.

In phd, you can check how often dec was corrected. This will give you an indication about polar alignment accuracy.

Cheers,

[Atreta]

thanks a lot, Wim

I have a GSO coma corretor but i don't have any spacers to use with it. Gonna have to import it along with an LP filter.

PHDLab shows 40' 30" polar alignment error, a bit on the high side, gonna try again this weekend to shorten it.

 

[alacant]

3 minutes ago, Atreta said:

don't have any spacers to use with it

Hi. 20mm should do it for a dslr. HTH.

[rotatux]

5 hours ago, Atreta said:

m8 - lagoon nebula 1x300s iso 400

Splendid, nice colors and I can guess more "hidden" data. With more subs and some processing (push more, strip some background, ...) a very nice image will come

Your T5i camera seems to be a modern one, maybe you could push up the ISO a bit (e.g. 800-1600) to reduce sub duration and get more frames per session, while keeping the best dynamic range possible ?

[Atreta]

7 hours ago, alacant said:

Hi. 20mm should do it for a dslr. HTH.

Thats nice,  i'm using a low profile  t ring,  but i have another one with about 10mm, so i'd need just another 10mm?

 

2 hours ago, rotatux said:

Splendid, nice colors and I can guess more "hidden" data. With more subs and some processing (push more, strip some background, ...) a very nice image will come

Your T5i camera seems to be a modern one, maybe you could push up the ISO a bit (e.g. 800-1600) to reduce sub duration and get more frames per session, while keeping the best dynamic range possible ?

Thanks,  that was just a test shot to see how guuding was.  I normaly use iso 800 with my imaging.  Gonna give it a go again  this weekend. 

[Nova2000]

The lagoon sub is nice