Guiding Setup

This is not simple, but it is wonderful. I’ve added a small guiding scope(QHY mini) and camera(QHY5L-II-M) to the mount. Sharpcap uses the guide camera for polar alignment; Stellarium will point the mount to my target; AstroTortilla checks that the camera is pointed correctly and adjusts the aim; and PHD2 continuously monitors the image from the guide camera and makes minute corrections to keep the aim perfect.

There are probably limits to how long the guiding setup can hold position but it’s certainly good for 90 seconds even with indifferent polar alignment.

On Jupiter’s Moons

This is a random setup shot through the 200mm lens where I was using jupiter to set my aim. It’s 1 second f/4 ISO 6400. It amuses me that Jupiter’s moons show so well. If you look at the inset you can see io, Ganymede, and Callisto. I checked against stellarium and they are the right distance from the planet – Callisto being 6′(arc minutes) which translates to 80-odd pixels in the image. The moons are all around magnitude 5 which makes them naked eye visible but I guess without a telescope they’d be lost in Jupiter’s brightness.

Neptune!

Neptune is almost at opposition and is magnitude 7.8 so imaging it isn’t really a problem. finding it in an image is a different matter! The pie shape above is due to me repeatedly rotating and cropping to align it with images from astrometry.net and stellarium. I stacked eight frames(60 sec, ISO 400, f/4 through the takumar 200mm lens) with darks and bias but it probably wasn’t necessary. I’m going to get another shot next clear night so i can verify it moving against the background stars.

Yep: Below is a single exposure as above just tweaked a bit for contrast. I’m pretty sure the green arrow is pointing at Neptune.

These were done, by the way, from my streetlight-blighted front porch which is a very convenient setup spot with a view to the south over suburban houses. There’s no way to polar align there but I can get within a degree or so and the guiding arrangement seems happy enough to compensate.

Milky Way Lucky Shot

We spent a few days at a cottage in the mountains. Very dark skies overhead although hemmed in by forest. I was delighted to see the milky way easily although not as vivid as in the image above. That is the result of four 30 second shots at ISO 1600 through the canon 18-55mm lens at 18mm f/3.5. This was just the camera on tripod, no tracking, no zoom.

Cassiopeia is lost in the profusion of stars but it was clear in person. Andromeda shows just above the trees right of centre. In one of the sub-exposures I caught a late perseid meteor just above Andromeda. I saw another one around the same time. For the image below i took the sub where i caught the meteor, duplicated it so i had three copies then fed it to Siril. Besides the usual process I used the ASINH transform to move the black point about half way.

A Quickie In the Backyard (With M31)

This is not very good, of course but it was very easy. I was a bit surprised to find that i had a clear line of sight to Andromeda last night around 10:30 pm but it was almost 30 degrees up so maybe not unexpected. I just took 3 shots at ISO 400, 60 seconds each through the takumar 200mm lens wide open at f/4. I combined the 3 shots with Siril as below. You can pick out M110 and M32 if you know where to look but I left a lot of detail on the table. It will only get higher in the sky from here so if i take my time i can do a lot better. This is about a 25% crop.

Siril workflow(from https://www.youtube.com/watch?v=tuzQL_1xe7c):
-Lights into desktop\20-08-07\lights
-Siril change directory to desktop\20-08-07
-Script DSLR preprocessing no darks no flats no bias
-B/W window to autostretch
-image processing/color calibration/color calibration
-image processing/remove green noise
-B/W window to linear
-Image processing/histogram: autostretch
-Image processing/asinh transformation: moved black point half way to the right
-cropped and saved as JPG


Pluto – But Not Yet

I was out last night to look for the comet – i didn’t have my mount but i did have the camera and tripod and it was a nice night so i took a shot near jupiter where i know pluto is hiding. I would say good prospects. The area is fairly dark and there are good guide stars. On the right is a shot from stellarium with pluto selected. On the left is the framing shot with the takumar 200mm lens wide open 2.5 seconds ISO 6400. The dimmest stars I can see are probably mag 9-10 which is a long way from pluto’s 14.9 but i’d like to think that i’ll get close by stacking and it will be good practice for neptune, ceres and vesta later in the year.

Target Pluto

Pluto is impossibly far away and wee – it’s like 3 billion miles away and smaller than the earth’s moon. However, it’s easy to find right now – within a degree or so of Jupiter. It is nominally magnitude 14 and, with luck, I my be able to pick up an impression of it later in the summer. I know that I have picked up stars that dim with the 200mm takumar.

In the image above the red outline is the field of view with my that lens.

In the image below, I have seen this magnitude 14.81 star in M101 shots so maybe…