Physopto

I was just about to post a reply, when I saw Olly's answer. Absolutely correct, I would say. I tried this when I started. Bought a 12" Meade for visual use but after a short while of use decided it was not really what I wanted. I then bought a 132mm William optics frac. I still have this, but have found that for the targets I wish to image that an 85mm aperture frac is more in keeping. The 132 is also not powerful enough for the deeper space targets, so either I fit a 2,3,4x convert or as these can cause problems for fitting your camera and other devices, buy a bigger frac. Yet more expense !!! The tracking of targets is important and requires some patience to get right, more so when using bigger scopes with more magnification. Larger targets require many more subs and often stitching together (mosaic). Using a smaller aperture can alleviate this, or even eliminate the need altogether. If you stay with visual it is another matter as Olly says. Try if possible/ask, in an Astro club before you buy and remember, your bank balance will be the decider, or her indoors 🤔 Do not rush in it is an expensive choice to make if wrong ! I know that now. Derek

Look in a scrap yard, you might just be lucky.

Just a point about the dew heaters. Mine are controlled by a kendrick controller that keeps the temperature a few degrees above the dew point. Also the 10 Micron mount control computer is under the mount and just keeps a bit warmth in its enclosure whilst swtiched on all the time. The QSI ccd does much the same for itself. As long as there is plenty of air circulation allowed from below, there does not seem to be a problem. Apart from thieves, I would not want to do this over a really long period. There are lifetimes of components to consider when power is applied. I am trying to move to a dark area, once accomplished I will build an observatory, however small ! 🙂

As Carole says, at star parties, I also leave my scope and mount out all the time. Sometimes for up to 10/11 days. I use two covers, the outer one is Gortex (difficult to get a hold of) and the inner a waterproofed nylon type. I leave the power on at all times for the mount and dew straps. There is enough air circulation, that so far I have never seen condensation the next day. Normally weather depending I cover over around 3/4 in the morning when finished imaging and everything by then may be dripping wet. By the late morning when uncoveredi don't see any dew still on the gear. I still leave it uncovered If possible for several hours to ensure that every component is completely dried out, just in case. I would never dream of doing this at home for fear of theft. Derek

Er no, photons are not Fermions, they are Bosons. Fermions have half interger spins, photons have a hole number, normally! In experiments it can be shown that photons can be produced with half interger spins, I.e act like Fermions. This is caused by the half-quantisation of the total optical angular momentum.. As far as Merlin66 needs, a star is so bright, photon arrive very quickly in droves, so I can't see a problem, short exposures I would guess are fine. Never tried what you are doing, very interesting work. For faint objects it can take a long time for enough photons to arrive so long exposures to get enough photons into the ccd wells producing electron counts.

They may be cemented together, be careful.

Photon are random in arrival and position. It takes time for a picture to become clear. It depends upon the signal intensity from the source. Physics 101. Look in any undergraduate physics book for the explanation. This is why our pictures of the stars and nebula can take so many hours to accomplish a final acceptable image. In daylight a photograph is possible in milliseconds because there are so many photons arriving. 🙂 Derek

Aye, and many can see in the infra red and ultra violet as well. We need expensive equipment to do so. Life just ain't fair! 😀

10 photons in 1 minute, or 100 photons in 10 minutes. You cannot just multiply the 1 minute result to get a 10 minute sub. The photons are random in placement so do not all fall in the same positions when recorded. So a 10 minute sub is filling in the blanks so to speak, resulting in a smoother overall picture. Hence a 100 minute sub will produce a much more substantially smoothed image. Several then can be added to increase the overall image intensity. Derek

Well David, that is bad news. He seemed such a genuine and nice guy. I recon that he will be sadly missed by many. Derek

Sikaflex 512 as used for caravan seals on roofs etc. It is UV stable and works. There is also Soudal FixAll sealant cheaper and works. Neither work on a wet surface! So make sure the surfaces are very dry before applying. Are you absolutely convinced the leak is actually coming from the bottom seal and not tracking from somewhere above? Best of luck. Derek

Getting old 🤣

Cracking job. Derek

I have met John, he is a genuine person who spends a fair amount of his time promoting astronomy. I also asked him to give a talk at our local Astronomy branch in South Shields. He did it without any cost to us, purely because I asked. His talks always show his enthusiasm, which he seems to effortlessly pass on to others. If I was in the market for a DOB he would be my one and only call. Have met several of his customers and all give glowing reports on his service and mirrors. I suggest reading around the subject, a lot, then talk to lots of real astronomy amateurs before coming to your own conclusions. I am sure you will find no complaints here. Derek

One can only dream 🤔

🤔 Grass needs a trim ! 😂

I have used the dust off for years. I just am careful to test it before each use. By that I mean to give it a blast away from the lens or filter first. Allways keep upright at all times in use. I use Baader Wonder cleaning fluid after the first dust off. Or Isopropyl alchohol. I also use Kim Wipes or lens cleaning tissue. Once the lens or filter is clean I dust off it again and examine for any residue, then repeat if necessary. Use plenty of Kim Wipes once only and discard. Use ISO on the Kim Wipes. You can fold them and tear again and again until you have a soft ended pad to gently sponge off any dust or crud. I have been doing this for years and never had any problems at home out in the field or on university lenses and other equipment. If you are not sure even now have a watch of the Astrodon demonstration for cleaning filters. Modern filter coatings are not the same as years ago. They are basically hard coated. Lenses are maybe the most likely item that can be damaged by rough handling/cleaning. I have never in over 40 years damaged a lens or filter. Just use common sense, watch some/several demonstrations before commencing your cleaning and read up what filter manufacturers say. After all they make the things and don't want a bad rep by giving out bad advice. If you are a member of Costco, they sell the Dust Off cans by the six pack at around £17/19. So not that expensive. Mirrors are a completely different kettle of fish. Never cleaned one so no other comment there! Derek

Astronomik did at one point sell H beta CCD imaging filters, I have one, but now only sell it for visual astronomy. Astrodons in H beta are still available. Derek

I have bought a few high value items from the USA. Focusers etc. You will attract VAT and Import duty. The import duty was and I still think about 4%. So as a rough estimate it will be 25% in all extra. It also as has been said cost for the Carrier here in the UK. There some crazy costs involved depending upon the carrier. Post Office can charge £25 as of about 6/7 years ago. DHL was far more reasonable at about £18 I think. The problem is you cannot import directly by yourself, it has to go through one of the recognised carriers or there would be a lot of cheating for the inland revenue/tax to sort out. As to the Astrodon filters, they are very good from my experience so far. Not sure they are vany better for the cost though than Astronomik. I have a set of Astronomik as well as the Astrodons. The first set of Astronomik filters had some bloom on stars. They were very swiftly replaced at no cost to me by the firm with quick action. Very pleasent to deal with. I would recommend them without hesitation. Astronomik are also now selling for a small extra charge a set of filters matched for focus, parfocal. Exactly how well matched I do not knmow, but I would bet it is very close. The Astronomik filters are only 1.1mm thick, and coated on both sides. There is no prefered direction of orientation. The thickness of the filter can make quite a difference in focussing, as the Astrodons are 3mm. Hence any small differences in thickness from batch to batch can and does cause focus problems. In all honesty so far I have not noticed this with the Astrodons. Here I have to be absolutely honest, I have used the Astronomik many times but only just taken first light a few days ago with the Astrodons, even though my wife bought the set for me over 4 years ago. One problem I did have with the Astrodons was an abismal lack of care in the edge coating on one of the 31mm unmounted narrowband filters. They had managed to splash or drop spots of the edge resin coat on the filter in several places. It was returned to Ian King and he sorted it out very quickly. Cannot fault Ian in any way and always try to buy from him. I contacted the boss of astrodon and I admit I was not particularly polite. The filter should never have been sent out in that state in the first place. The Astrodon reply was that they were experiencing some technical problems with the narrow band filters but it would be sorted out the next year as they were outsourcing the filters to be finished. But there was no actual apology as such if I remember correctly. Having said this I still would recomend Astrodons as I can see no further faults. Hope this is of some use. Derek

End to another Star Camp. Made some new friends and caught up with others. Been 4 years since I was able to get to the camp other than just visit. Just hope I can get to another soon. Mike Annette and I travelled back across to the north east in just over 4 hours stopping off at Dumfries for a short break. A bit of rain but in all a nice day really. As everyone says thanks to Lesley and Ralph for a cracking Friday night banquette. Could not have been any better. Mike, as always was his usual cheerful self. A bonus was that I got a few subs as the weather played ball for 4 nights early in the week. At some time in the future, if I get the time, I may even do something with the images. 😱 Derek

No We remember well!!!! 😂

Well it never rains but often pours. Dawn slipped in the shower and broke a finger. Just returned from getting it xrayed I Stranraer. Jim says it is foggy all the way back. Had a look out and I am set up for later on if it is clear enough. As Damian says moon visible but will be gone shortly 😊 Glad you got back safe and sound Damian, been great to see you again. Derek

Thanks Damian, just relearning Pixinsight again after 4 years of doing no imaging. Oh the fun......NOT!

Just for Ian as he keeps saying he never sees anything I image. So here is a straight download without any processing at all. 1000 seconds Ha from 30th October at 0330 approximately. Weather was just closing in so last image of the night. Taken on QSI 683 wsg8, 85mm Tak BabyQ Derek Mounted on 10 Micron GM 1000hps and no guiding, Astrodon filter.

Hi Michael, Same here, had 4 good nights but clouded out last night, some rain as well. But today is as they say another day and you never can tell for sure. Hope you all have had a great star camp so far. Spoke to Keith the other night before leaving home, that was a pleasent and unexpected surprise. We had a good night in the warm room with plenty banter and a few good drams, so just waking up now. As I said regards to everyone. Derek