Disastrous Night - Help / Advice Needed

[agthomson]

Okay, this is a multi-part question, but instead of creating a few threads i'll bundle them all here as they are all related to AP.

1. The scale on the side of my HEQ5 seems off. Is that common? I'm at ~56.5N, but to get polaris in the polarscope, or evn when using SharpCap, I need to crank it up to 59. Not a huge issue, but beginning to question things! I re-set my HEQ5 to what it should be for last night's session, which is the 1st of the season (and only my 5th with the HEQ5) and just assumed SharpCap was telling lies before.
    
2. I'm polar aligning, then fine-tuning in SharpCap (also normally used for capture), using PHD for guiding and ASCOM/StellariumScope for GoTo and 3SA. I made the mistake of updating software a few weeks ago in preparation for darker skies and the connections were very unstable to say the least. Couldn;t 3SA properly, telescope wouldn't slew to a target and the telescope and Stellarium weren't sync'd. Having 3 or 4 pieces of software open didn't help - can I simplify this? I'm really considering ASIAIR as I only own ZWO cameras and a compatible mount. Looked at SGP and APT before but it seemed they also needed 3rd party software, or did I miss something?
    
3. I made several mistakes last night in a rush as it took close to two hours to work all of the bugs out. I have lost a bit of faith in SharpCap for image gathering (plus it can't dither properly) so gave ASICAP a chance (mistake 1). I have an Optoplon L-enHance filter for some Ha targets and to deal with LP, so targeted the Heart Nebula. 30s check exposures in SharpCap with 500 gain looked very promising. I forgot to switch on the cooler when I swapped back from SharpCap to ASICAP (mistake 2) but temps seemed stable at 1.5deg in all images. I also imaged at RAW8 (is this a mistake?) and imaged directly to .PNG as opposed to my usual raw (mistake 4). For some unknown reason I settled on 3min subs at unity gain (mistake 5) and the resulting images are unusable pretty much. I have attached a single sub.
   
   My 3rd question is does the combination of all of those mistakes explain the image I have, or can I narrow it down? I expected the green hue due to the filter, and was aware of the very bright star to the right of the image. The moon was out but relatively far away. I seem to have blown out the detail of the nebula, lost all the faint detail, and looking at the histogram I have lost a lot of data to the left of the curve. The image is also beyond noisy.

 

Any help would be much appreciated!

[Peter Drew]

Always trust Polaris, not the scales.     🙂

[ollypenrice]

Regarding polar alignment, have you checked the alignment of the polarscope within the body of the mount? (By day, aim the polar axis of the mount at a distant point like a steeple top and rotate in RA. The crosshair in the middle of the reticle should not describe a circle but stay on the steeple top. If not, adjust it.)

However, you are not aligning your tripod, you are aligning the RA axis onto Polaris, so the leveling of the mount and its scales are not important anyway.

Why do you say you've blown out the detail of the nebula? It's hardly visible so you can't have done. When you have a full stack I don't see why it wouldn't stretch nicely using either Levels or Curves.

Olly

[agthomson]

14 hours ago, ollypenrice said:

Regarding polar alignment, have you checked the alignment of the polarscope within the body of the mount? (By day, aim the polar axis of the mount at a distant point like a steeple top and rotate in RA. The crosshair in the middle of the reticle should not describe a circle but stay on the steeple top. If not, adjust it.)

However, you are not aligning your tripod, you are aligning the RA axis onto Polaris, so the leveling of the mount and its scales are not important anyway.

Why do you say you've blown out the detail of the nebula? It's hardly visible so you can't have done. When you have a full stack I don't see why it wouldn't stretch nicely using either Levels or Curves.

Olly

Olly, thanks for that. Checked the polarscope in daylight and all is fine, so just working off the assumption that the scale is inaccurate and there's nothing to worry about.

Regarding your second point, that was my feeling when capturing images - they seemed fine and would likely stack quite well (albeit a little green due to the filter). When stacked, the solid colour in the middle of the nebula and the bottom right of the heart are essentially a solid colour with no distinguishable detail. This might be a stacking issue, and something I need to play around with. I haven't been able to stack in the darks I collected at the same time as these have totally thrown off the image calibration (made it very noisy and neon green), but will take another look this evening. Maybe DSS is the area I need to focus on.

There may also be an issue with the debayering that I need to look at which will be hard given I only have debayered PNG files. Serves me righ tfor trying to cut a few corners.

[jimjam11]

In the UK time is your most previous resource because clear dark sky is rare and wasting it is incredibly frustrating...

If your setup is temporary you need to be able to polar align and get running quickly by leveraging as much automation as possible:

1. For polar aligning the fastest option is Polemaster. It isnt cheap but you can be accurately polar aligned consistenly within 5 mins. Sharpcap worked ok for me, but it uses your guidescope with a narrower FOV and all to often it failed for me which resulted in wasted time and frustration.

2. Dont bother with any alignment routines (or the handset?), they also waste time. Once polar aligned I open SGP and 'connect all'. I then slew to a bright star (such as deneb at this time of year) and perform a solve and sync. Once this is done the mount knows where it is pointing and you are good to go. Nina is a free alternative to SGP and can do similar: