DEC guiding problem using PHD

[Thalestris24]

If I meridian flip or move more than about45 degrees from one target to the next, I usually do a recalibrate.

Thats in brain again. Then mount. Top left of the dialogue box.

wont switch on if the camera is exposing. ..

You shouldn't need to with PHD2 though there's nothing stopping you of course!

http://openphdguiding.org/man/Basic_use.htm

Louise

[alcol620]

Just one outstanding point. When using PHD is the handset set up for tracking in sidereal or PEC + sidereal or doesn't it matter? Obviously a PEC run has to be carried out first.

[Thalestris24]

Just one outstanding point. When using PHD is the handset set up for tracking in sidereal or PEC + sidereal or doesn't it matter? Obviously a PEC run has to be carried out first.

See my post #20. There's no need to bother with PEC, especially when your just trying to get going. I've never done it!

However, see what your user guide says about PEC and the handset settings. I'm sure just sidereal will do for now

Louise

[alcol620]

Thanks Louise

Hope the weather improves soon.

Best regards

Alec

[alcol620]

Hi Louise

Outside for a few hours last night trying to get images of the Leo Triplet. PHD seemed to work OK after polar aligning the scope. Occasionally the DEC axis got into rather large variations and I had to increase the value allowed for correcting. May have been due to the odd gust of wind? At the end of the session I pushed the exposure time up and managed to get a 600s image with little or no star trails. On that basis I assume that polar alignment and the operation of PHD must have been fine.

I now  have an issue with Flat frames not removing dust bunnies when stacking in DSS. I assume a master flat frame should be produced - no sign of one. No idea why? I will post on the appropriate Forum for help.

Thanks again for your help.

Alec

[Thalestris24]

Sounds good! Yeah, could be wind. Flats can be tricky to get right. They depend on nothing changing in the imaging train between taking lights and taking flats. Flats are kindof like a negative of what the camera sees. When you combine with lights they cancel out the dust bunnies, vignetting etc. When you include flats in the registration and stacking you should see DSS going through and adding each flat individually and will eventually produce a master flat. If you then re-stack you can select the master flat rather than adding in each individual one. On a fast computer it doesn't really save much time.

Louise

[alcol620]

Hi Louise

Obviously something amiss as the flats of which there were 20 are not combining to produce a master. More stuff to fiddle with and get right!! Have another go tonight and in the morning. Seem to be lucky in the East at present1

Regards

Alec

[Thalestris24]

Hi

Are you following the DSS 'prompts' i.e. under 'Open picture files' it has 'dark files...' then 'flat files...'. When you click on that you will than have to navigate to the folder which holds your flats. You then select all of them (ctrl+shift on last one) and click on Open. All the flats should then be added under the lights and darks. You can probably accept the default settings for registration and stacking. Once it's been through the registration process it should create master darks and master flats in their respective directories, then include them in the stack.

Louise

[alcol620]

Hi louise

Yes did that. I have also posted the question on the following Forum and getting some feedback, including the fact that I have 'found' my master flat file!!!!!

Flats not removing dust bunnies

 in Discussions - Software    

[Thalestris24]

Hi

I'd recommend moving lights and calibration frames to separate named folders so you can keep your data organised.

Flats are usually taken using a flat panel or laptop screen with Notepad opened. The aim is to get even illumination without any gradients and with the histogram about a third from the left. When loaded into DSS they will individually look quite dark.

Louise

[alcol620]

Hi Louise

With PHD and your help and guidance, I have managed to produce the attached image of the Leo Triplet.  20X100s, 3X300s and 1X600s using a Canon 1100D on my 8SE celestron scope

Thanks again

Alec

[Thalestris24]

Hi Louise

With PHD and your help and guidance, I have managed to produce the attached image of the Leo Triplet.  20X100s, 3X300s and 1X600s using a Canon 1100D on my 8SE celestron scope

Thanks again

Alec

Hi Alec

Well done! That's better than anything I've been able to get! You didn't mention calibration frames (flats/darks/bias)? They will improve your image and make processing easier

If you can get another 20-30 x 600s I think that would be good  Don't forget to leave a reasonable time between subs and darks to let the sensor cool. Also, avoid using liveview for any length of time as that really heats the sensor. Heat = noise!

Louise

[alcol620]

Thanks Louise

I did add darks. Noted your point about leaving time between subs and darks. 20-30X600 that's a lot of time out in the cold!

Alec

[Thalestris24]

Thanks Louise

I did add darks. Noted your point about leaving time between subs and darks. 20-30X600 that's a lot of time out in the cold!

Alec

Heh heh

You don't have to capture all your data in one go! If you can get some more 600s subs you can stack them with your first 600s sub. I think once you have 10 x 600s the stacked image should look a lot better I'm not sure what the optimum time between subs/darks should be. Maybe 60s? Probably not less than 30s. I guess you'll have to experiment You could take a fast dark, see what the reported temp is, take a 600s dark, see what the temp is, wait 30s, take another fast dark and so on. Once you've established an optimum 600s exposure cool down time you can create a dark library based on it and take 600s lights with the same time gap.

Louise

Louise