Felias

We had some leftover budget in the school, so I bought a Lunt 40 mm, now that we are approaching the solar maximum. I tested it on Monday, and was quite amazed at the crisp views of some very nice prominences. Looking forward to playing a bit more with it! I must add that 365 Astronomy was great at customer service. When I received it, the front was loose and I couldn't rotate the etalon wheel without moving the whole cap. They took it back, examined it, and returned it without any shipping costs, and very fast. In the end the scope was fine, and I'm keeping it.

After months without a chance to go out, I finally could test my new camera last night. I thought that the NA nebula would be a good target, and I could compare it with the one I took a year ago. All things considered (no astro darkness, half moon, light pollution), I think I'm getting much better results now. Hopefully there will be more chances to test it over the summer! 162 x 1 min lights, ISO 800 WO Z61 II, on a Star Adventurer Canon 700D astro modified Stacked, colour calibrated, and slighlty stretched in Siril, passed through Starnet, and processed in Photoshop. Starnet left some artifacts on the bright star on top of the image, I couldn't completely remove it. I merged it with the original file, but I don't think I got it right. Anyway, I was mostly interested in looking at the nebulosity, to see if the camera works with the IR filter removed. Seems fine to me, but any advice welcome!

I have just come back from a fast session with the Dobsonian outside. It was too windy and kept shaking, but that large group near the edge was impressive through the 9mm eyepiece!

Hi! I have just bought a Lunt 40 mm for my school, but I am having trouble setting it up. I have managed to focus with 20mm and 9mm Ploss eyepieces, but the tuning dial does not seem to work well, I can't see anything but a red disk. I have noticed that the whole filter cap is loose, and that I can rotate the whole thing around, not just the wheel. Is this normal? I don't want to tighten the screws myself, in case it's the wrong thing to do. Some pictures to show what I mean: I can turn the front 360 degrees, I assume this is not right? Any help appreciated!

My daughter made me a picture... she's just starting to draw recognisable human beings! Also, I bought myself this... ...and a little LEGO Friends set for her, so she won't be jealous. 😇 I'll probably take the ISS to my lab in school, it will look good on my desk.

Nice. I'm going outside with my pupils and our new 8" Dobsonian at 5pm. I had checked online to make sure that there would be sunspots, but it's nice to see a shot similar to what we will see with the Baader film, thanks!

I recently had a chance to talk to the members of a rocketry club from York uni, and their clashes with the police for keeping explosives in the campus were ridiculous. I assume that terrorists wouldn't be asking permission to the campus authorities, but maybe I'm too naive to be a policeman... 💣

As a follow up, I have tested the StellaLyra this evening, looking at the moon. It seems good, the image was quite sharp once the moon was high enough, even though there were thin clouds covering it most of the time. I am not sure that I have the right balance, though; when pointing to Arcturus, which is almost 60 degrees high, it shifted to the vertical position and it was difficult to keep the star in the crosshairs. I may need to slide the tube with respect to the altitude axis... Anyway, a shot taken by a pupil with her phone, which was much better than my cheap Moto G -I just got a big white blob every time I tried!

Projectile motion is also part of the Physics curriculum, so a football cannon would be fun! 😅 But yes, I can't complain about the behaviour, I know I can leave the telescope outside while I go back to my lab for more eyepieces, and no one will touch it. It's a nice feeling...

Bought an 8-inch StellaLyra Dobsonian from @FLO, for my school. Also a Baader solar filter. Arrived on Thursday, but brought clouds as usual, so I have just tested it this morning. So far so good, I saw the #3030 and #3031 sunspots with good detail using the 9 mm eyepiece. Looking forward to testing it at night, or at least with the moon in the evening!

Mmm, it may be worth having a look at a single sub. Even under the difficult conditions these days, the NA nebula is quite forgiving, and 40 min should give a noisy but more detailed image than the one you have posted. I have just bought a modded Canon 700D, and although I tried to test it with the same target, I forgot to charge the battery and had to change my plans last Wednesday. But I took a single photo, 40 seconds, ISO 1600, with a WO Z61 on a Star Adventurer. This is what I got: Yes, very noisy, as one would expect of a 40-second exposure (and it was low and washed out by city lights, I didn't use filters), but its characteristic shape is there, and the nebulosity stands out from the stars (after a bit of curves and levels in PS, plus lowering the cyans). So I don't think it's a matter of choosing an "easier" target, there is something definitely odd about your picture. It may be the stacking, without flats the gradients may be dominating the photo. The stars look too red, so as Astro Noodles says, have you colour-corrected the photo? If you post a single photo, it may be easier to see if it's the stacking/processing, or if it is the capture of data that needs improving. Edit: I have just noticed the mouse pointer in your photo. Is it a screen capture? It probably looks worse than a file saved directly from gimp.

I have just finished processing my images from two nights ago (taken from the fields near Petham, roughly Bortle 4). I managed about an hour and a half of data on M101, which was conveniently high in the sky. Of course, there wasn't proper astro darkness, and by the time I was taking darks and flats, it was almost morning. But it's only my second attempt at M101, and I'm happy with the improvement (the bar was quite low, though, having only taken 30 min of data my first time). I decided not to crop the star field (just the stacking artifacts) and show the galaxy in context. There are quite a few other galaxies, identified in astrometry.net (although it left out UGC 8837 and UGC 9071, which are easily seen above 86UMa and on the centre-left of the picture, respectively). I've seen very saturated photos of M101 around, but I thought I'd not push the colours much., to make it look more natural. The HII regions still pop out, quite bluish in my unmodded DSRL. They gave me some trouble and I had to start from scratch after my first processing when I realised that Starnet had identified many of them as stars, and removed them from the picture. I finally decided to reduce the stars in the old-fashioned way of creating a mask using the selective colour tool in PS. I wonder if anyone else has encountered this problem in widefield pictures? Comments/suggestions welcome, as always. 100x1 min subs. WO Z61, Canon 77D on a Star Adventurer. Stacked and colour-calibrated in Siril, processed in Photoshop.

I spent last night in the fields near Petham village, so I captured the 9% waxing moon during sunset, and then took a picture of the conjunction of Mars and Jupiter before sunrise. The former is a 50mm shot with a Canon 77D, the latter is a single shot with a WO Z61 and the same camera, 8 seconds, ISO 800. In between these shots, I imaged M101, but I haven't processed it yet... It was a clear night, but humid, easily above 90%. The telescope was soaked in the morning, I had to put everything to dry before going to bed!

The Oort Cloud might extend even further than that (the classic, conservative estimation of its radius is 50,000 AU), so although they have no idea of the actual position of the Voyager, the quote is not completely bonkers.

Or maybe it is leaving the Slow Zone and entering the Bottom of the Beyond... 🐕🐕🐕🐕🐕

Thank you for all your kind responses. All good advice, I believe, though sometimes contradictory! ✨ You have given me much food for thought, and it seems that I need to reflect about this a bit longer... 🤔

Thanks. I hadn't thought of fan-cooled cameras, they may be a very good option in my case. I do carry a surface pro anyway, just to take my flats, only that I keep it stored until the end of the session. I could use it for acquisition, although I would worry about dew; it gets so bad where I usually go that most of the year my equipment ends up soaked, so I don't know how it would affect the laptop. The Altair 183 has a rather small sensor, 15.86 mm. I was thinking of something closer to APS-C size, so what about the Altair 294C or 269C? I haven't read much about them, compared to the ZWO options that most people seem to use. More food for thought! Well, it's not as much the little opportunity, as it is taking as much as possible from my tiny windows. If the data a I could gather in my limited time with a cooled camera were a significant improvement over those captured with a DSLR in the same time, I am willing to spend the money, even if I can't go out as much as I'd like to. If the setup is going to be so complex that I'd use up my time getting the rig in place, focusing, etc, then it's not worth it. That's essentially my dilemma.

I have been thinking of upgrading my camera (currently a Canon 77D, unmodified), but should I get a modded DSLR or a CMOS cooled camera? I have few opportunities to take images during the year, and when I do I rarely get more than a couple of hours of data (I work 6 days a week, sometimes 7, and I have a 4-year old daughter, so I don't expect to increase my number of free evenings any time soon). Besides, I don't have a garden, so I need to drive to the fields, and my setup needs to be light and easily portable (WO Z61, Star Adventurer). So although I've been considering something like a ZWO ASI294 colour camera, I was wondering if it would be overkill. As I see it, there are advantages to the DSLR: -Fast setup, I can get everything ready in 20 min. -Cheaper, but I still would need to buy a new camera since I use the 77D in daylight as well -I could easily use it with other Canon lenses -No need for power packs/more cables. Since the Star Adventurer uses batteries, I don't carry one now, and would have to factor the extra cost and weight if I bought a cooled camera. -No need to carry a laptop, I'd just plate solve using the DSLR screen -as I do now. -The star adventurer only lets me capture 30 to 60-second subs at this moment, so will cooling make such a big difference? I'm not upgrading my mount, I don't feel like carrying anything heavier uphill every time I go out. So I've seen the amazing pictures people capture with cooled cameras, but considering my restrictions, do you think it's worth taking the plunge? Would it be a significant improvement over a modded Canon? Any thoughts welcome!

Personally, I have found that using starnet seriously damages my photos. Maybe it's my noisy data, but the circles around the stars are horrible, the pictures end up looking like Emmental cheese -and I suspect it increases the noise as well. You can see those circles clearly in your photo above; it's bad enough for the bigger stars, but those around the smaller ones create a "foamy" background or red and green noise. I now use a star mask in photoshop to protect the stars; it works fine, especially if after each stretch one uses the 'fade' function, and doesn't create such artifacts.

Thank you!

My attempt, a fast 10-min processing: photometric calibration in Siril, then all the rest in PS. Stretched using asinh10 curves, then just the camera raw filter for clarity and denoise (I could have smoothed it further, looking at the jpeg).

Following step by step the Siril tutorial will teach you how to stretch your image: https://siril.org/tutorials/tuto-scripts/#tuto-3 Personally, I have found recently that successive asinh stretches, done carefully, make it redundant to tamper with the histogram any further. But my data are always very noisy, so there's that.

Thanks. I'm used to this kind of noise, since I also have a Canon and can't normally spend more than three or four hours in the fields, so my SNR is pretty low. I deal with a dirty background and horizontal bands quite often! I've been thinking of buying a CMOS for the summer...

Thanks! It's a nice place, and the pollution is not too bad towards the South. I find that it is a good spot for imaging Sagittarius in the summer (or as good as it gets in the Canterbury/Ashford/Folkestone/Dover quadrangle). A bit further down, towards Waltham, it's a bit darker, but the public paths are rather untended. Thank you. I hope you don't have lights in your garden, though! 😁

Definitely better! 👍 Perhaps still a bit green? Removing the green noise in Siril takes just the click of a button. I was having trouble myself with getting the right colours until I started using photometric calibration. As for the noise, I have lately been doing successive asinh stretches, followed by a levels adjustment in PS. This has kept the noise from messing the background too much, and has made it easier to correct with a filter when I have finished stretching.