2 replies to this topic

[topcode]

I am going to be imaging in 8-14um IR, yes, I am aware of how impractical that is, no, you cant stop me. Obviously, since I cant afford a proper camera for this, ill be using, bottom of the barrel microbolometer gear, meaning I will get basically no signal, nothing to align.

But, I can guide, so problem solved I just keep the image pointed straight ahead for several nights to get something to show up right?

Nope, I will have to dither especially so because these cheap things also have horrible non uniformities in the sensor.

 

The solution is that I need some way to convert guiding data into image alignment data so I can actually stack this stuff. I have no idea how to do that. Send help.

[topcode]

I'm gonna be honest guys, I really need some help here. I don't want not being able to stack being my downfall here, because I know in theory stacking this is possible, I just don't know how.

 

The second best way to do it would be to stack every section in between dithers, and hope enough of a bright spot is there to align, but that still sucks severely.

 

I do understand that there probably isn't ready made software for this, but I have no idea where I would start to make software to do this.

[whwang]

Do you use OAG?  If so, it's definitely possible to use guide data to stack imaging data.  Conceptually it's quite easy.  Unfortunately I don't think there is any off the shelf programs designed specifically for this.  You will need to figure out by yourself how to retrieve guide data and to convert them to offsets prior to stacking.

 

My guess is that even dithering is not enough to overcome sensor uniformity.  In this wavelength, the color and brightness of sky can be varying in a short timescale, and this leads to varying of flat field.  This can make detections of extended features (nebulas, large galaxies, etc) extremely challenging.  For point-like sources (stars), it's easier, but still not easy.  A standard technique is to conduct a two-point dithering: alternating your telescope pointing between two positions at a high frequency, and subtract images taken at one position from that at the other position before stacking.  This can effectively remove background structure caused by the sensor non-uniformity and leave a positive-negative image pair for a detected star.  But you won't get pretty pictures this way.

 

Do you already have that camera on your scope?  If so, you may try pointing it toward Venus, Moon, Sirius, or Vega, to see if you get any signal at all.  If not even on such bright objects, you can put a full stop to this project.