M38 – IMT3b Observatory

Viewing Report 18th March 2025 Tenerife

20:09 – 23:28

I have decided tonight to start to retake the 6 objects from the previous two nights. The Moon definitely had a massive effect and so did the cloud. I want to see what it’s like imaging without the Moon and clear skies. The Moon comes up at 11:16pm so I will image from when it is dark until then.

I have had a few intermittent problems with focusing over the last few nights. I have now realised it is worse when their scope is pointing directly up so the ratchet focuser must be slipping. I have taken it to pieces this evening and then reattached the EAF ZWO electronic focuser and bracket. It now seems to be working fine. Due to this issue I lost the first 90 mins of imaging this evening. It’s now 9:30pm and I’m back up and running, but will need to delete the first 7 or so images from this evening that are out of focus.

I started with M38 the open cluster in Auriga and managed to capture around 1 hours worth of 120s subs.

It’s worth noting that there is a large black circle on the flats, I thought this was due to a smudge on the filter, however I have now cleaned that and it is still there. Therefore it must be on the corrector plate so I will look tomorrow.

Also I had some problems tonight with the guiding suddenly jumping. I put this down to the stretchy USB cable running to the mount getting caught, however on changing how it was connected I still had the issue so I need to further investigate. I will change the cable tomorrow to using WiFi which I have just found out I can do.

I took flats and darks.

By way of an update, it transpired that some of my problem with the guiding jumping was the 4s exposure I was using, reducing this to 0.5s-1.0s resolved the problem in the main. The only time I saw this again was then when the scope was pointing low to the North Western horizon possibly being effected by the street lights.

Viewing Report 20th March 2025 Tenerife

20:18 – 01:20

Following on from last nights cloudy weather, I have setup again tonight, and it is looking clear. I am imaging M38 again, I will use 120s subs and take the appropriate Flats at the shorter exposure as with the Triband filter it suggested 750ms on Auto however these are far to bright so I will reduce back to 500ms.

After 3 hours I had not only gathered much better data for M38, but also the clouds once again on this mountain had formed. I waited until 1:20am and then packed up as it was not clearing.

Viewing Report 16th March 2025 Tenerife

20:34 – 06:30

Setup in the light polluted Adeje town north of the TF1. We are staying in a 3 story townhouse and I am imaging from the 2nd floor terrace.

I have brought with me for the first time the ZWO ASI2600MC AIR and I am imaging with that using the small 220 built in guide chip for guiding and imaging through the Esprit 100 whilst trying to cut down the light pollution using the Antlia Triband RGB filter.

Focusing on completing my Messier collection, given the full moon, I am imaging M38 an open cluster. Taking 60s exposures to try and keep the chance of over exposing the stars, I am also West of the Meridian and at a starting imaging altitude of 55 degrees thus limiting the ingress of light into the telescope.

After 2 hours I moved on to M48 another open cluster. Again it was reasonably high at 42 degrees to allow for 2 hours of imaging before I hit the lights of the buildings. Imaging overhead is clearly what is needed after looking at the last few images of M38.

Another 2 hours completed and I then had a hard choice of what to image past the meridian, away from the Moon but before the lights of the buildings. I landed up targeting M109 to the left, along with NGC 3953 to the right of centre and NGC 391 to the far right. One of the stars making up the constellation of Ursa Major, 64 Gamma Uma can be seen. I went back to sleep and woke up around 7am to shut down the imaging run. A good first night.