Letchworth and District Astronomical Society - LDAS

03/12/2025

The Veil Nebula in Cygnus.
I shot this a month or so ago with an Askar FRA400 and reducer. 194 x 90s exposures gave a fantastic result.

03/12/2025

The Sun, today.
Another glorious sunny day. I was out for most of the day but I managed to get half an hour in my observatory at about lunchtime. Here are three images. The AR4294 group is huge.

23/09/2025

Pickerings Triangle, Cygnus.
Pickerings Triangle (NGC6979) is a part of the Veil Nebula supernova remnant in Cygnus. I recently purchased an Askar 103 apo refractor and thought this would be a good test, with a colour 071 camera, as the area has not just the nebula but lots of stars, too. I only got 34 x 2 minute sub frames and I was rather amazed at how good the result was. According to Pixinsight the image contains 24573 stars! The Askar seems to have really excellent reolving capabilities, something I have also observed when using it on the Sun.
The image would look tidier if I cropped out the part of the western veil along the edge, but it seemed a shame to remove it so I left it there.
Applied dark frames, flats etc and used Blur Xterminator and Noise Xterminator during processing.

30/08/2025

H-alpha, sodium and magnesium line images from the MLAstro spectroheliograph.
I hadn't used the SHG for a couple of weeks and today decided to get it into action again. It was fairly cloudy but there were enough breaks to get some scans done. Previously, I did my scans at 8x sidereal rate but today I used 16x. I also did a reset of the non-telescope focus set up to get the best chance of decent results.
It looks like I nailed it, good well resolved images, somewhat spoiled by what looks like a spot of dust on the slit. Still, I was pleased with what I got. Didn't get a chance to try ther Ca line.

03/07/2025

NLC's last night.
Looked out to the north at 0200 this morning and some NLC's were visible on the horizon. I took a chance a set a camera\ running and went back to bed. Here's what the camera recorded. Each frame of the video was individually metered so the brightness is consistent through the video. Of course, in real;ity the sky was brightening as dawn aproached.

01/07/2025

https://youtu.be/81GlgMLQItY

A time lapse video of the Sun from 0626 until 1517 UT. 223 x 2000 frame videos were captured and the best 100 frames of each capture were stacked and proces...

16/06/2025

Some Solar Observations.
Being retired and having an observatory can create a problem, albeit a nice one to have.............. too much data. Any time the Sun isn't obscured I go out and have a look whatever the time of day. While the seeing generally deteriorates as the day gets warmer sometimes you can get good results late in the day.
I have a lot of data from the last few days and I'm just catching up.
On Friday there was a ISS transit visible from my observatory in Moggerhanger. The sky looked very promising, until the time of the transit. Right on time a cloud rolled by and totally messed up the imaging opportunity. I had a camera on the Lunt 152 and another on an Intes MN106 (white light). I had to go through the video files I captured frame by frame to find a frame showing the ISS. I did find some but there was so much cloud it wasn't worth trying to stack a set. So, here are single frames.
All rather frustrating!
Also, here are a few pictures from Saturday and this morning. I had a bit of luck this morning, the seeing was good enough to put a 4x Powermate on the Intes MN106 allowing operation at 6.1 m!

16/05/2025

New tools for solar astronomy.
There are some interesting developments going on with equipment for solar astronomy. Until recently we had etalon based systems from Lunt, Coronado (no longer in business), Solarscope and Daystar. Now we have the Skywatcher Heliostar (H-alpha), Acuter (H-alpha and white light), the MLAstro SHG700 spectrohelioscope (camera only, any wavelength) and a 300 mm Newtonian from Soleye in Hungary (H-alpha).
I now have a SHG700 spectrohelioscope (since Monday) and have got it up and running. It's a completely different way of doing things which makes it very interesting. A spectrohelioscope uses a slit to isolate the wavelength you are interested in and then scans across the Sun and records a video file. Specific software (J'Solex, free) is used to create an image. If you are interested take a look at the MLAstro website, https://mlastro.com/
The owner, Minh, is based in Vietnam, and provides rapid feedback to posts and questions.
Anyway, here is an image from lunchtime today. This is the H-alpha wavelength at a band pass of 0.3 A which is much narrow than even double stacked etalon systems, this creates the high contrast in the image. For comparison, I've added an image from the Heliostar. It has to be said that the SHG is about a third of the cost of the Heliostar.

14/05/2025

The Sun, May 14.
Today, I had more time to get used to the MLAstro SHG700 spectroheliograph. The weather was excellent, which helped a lot!
It's a very different way to create an image compared to using an etalon based system and more software to learn how to use.
This is the best I've got so far. It's at the H-alpha wavelength, I haven't tried any others yet.
I've included an image from the Heliostar for comparison.

11/05/2025

Solar Time Lapse, May 11.
Today provided an opportunity to try and get a time lapse of ther Sun, lovely clear air and no clouds - when I started ! I noticed some activity on the limb where the active region AR4079 had been and some large prominences nearby. I recorded 2000 frame videos separated by 60 seconds and stacked the best 100 frames of each video. The stacked files were sharpened in IMPPG, batch processed with the Solartools process in Pixinsight and then a gif created in Photoshop. Final conversion to mp4 was in Power Director 14. The time runs from 0742UT until 1255UT.
Lunt 152DSII solar telescope and ZWOASI 462MM camera.

01/05/2025

The Sun, May 1st.
Another beautiful day to do some solar imaging. I have H-alpha images from a Lunt 152 DSII with a ASI678 camera, and a 'white light' image from a Intes MN106 and ASI174MM camera with Baader ND3.8 solar film and Baader 7.5nm continuum filter.
The detail in the full Sun images is excellent and the etalons are performing as well as ever after 15 years.

29/04/2025

The Sun, April 29.
A couple of months ago my Lunt 152 solar scope had a 'fall' while it was off its mount. Images taken after this didn't look good so I sent the etalons to Lunt in the US to get them assessed and, if necessary, repaired. As luck would have it Lunt found them to be undamaged and suggested I look at the focuser as a possible cause of the poor images. I can only assume that if the blocking filter is significantly unaligned with the optical axis of the etalons that it will affect the images. As far as I could see the focuser was fine. Anyway, yesterday the etalons arrived and were quickly back in action. I had more time to check them out today and I was delighted with the results. I also compared the results of the double stacked Lunt with the Skywatcher Heliostar. To me, the Heliostar easily competes with the Lunt even though it has half the objective diameter of the Lunt.
I much prefer monochrome images to colour versions, apparently the human eye sees contrast much better in monochrome. I agree.