Astro Noodles

Hi Adrian I was watching a podcast by Dara O'Brien (who has recently taken up astrophotography). He made the analogy that astrophotography from a light polluted city was like taking up scuba diving but only doing in the river Thames. 😁

Here is last night's rather disappointing effort of M13. I took 250 20 sec subs at ISO 1600 stopped down to F5.8. This is just the best 9 stacked. Issues that I can see (apart from noise and dodgy colour balance) - 1) Star trailing. I just can't seem to the Skyguider pro to behave. It seems to be tracking slightly too quickly if anything. However, it does seem to be getting slightly better than first efforts. 2) Bloated stars. Having tried lots of different things, I think the star bloating is due to the lens not being able to focus all wavelengths of light correctly. 3) Insufficient data. Tonight I will go for ISO 1600 at F3.5. All in all, a lot of effort for a rather disappointing result. 🙁 Here's on with a bit more processing.

Perhaps a plane ticket to somewhere dark at night.

I think it would be a hefty book because different cultures often have different myths. The two books I have mentioned do briefly cover the mythologies associated with certain asterisms (Pleiades, Taurus, Orion). Associations between the Taurus constellation and a bull/aurochs seems to go back into pre-history. Myths associated with Pleiades seem to identify them a seven sister/young women in many cultures. It is a fascinating subject. 🙂

Hi Niko Both of these books have extensive footnotes and bibliographies. You could use them to track down what you are really looking for.

Hi Niko I have read these and they might be the sort of thing you're looking for: 'The Human Cosmos - A secret History of the Stars' by Jo Marchant 'Beneath the Night - How the stars have shaped the history of humankind' by Stuart Clark

Lightning ?

That looks like a medieval torture device, 🤣

So what do you think we should do about it ?

I certainly will keep on imaging and observing. Unfortunately the weather has rather put an end to either in May. I've only managed a single hour's observing in the whole of may. This weekend looks promising. I have booked Monday off so I can stay up late on Sunday night. I'm going to try the Sadr region.

Good point, and turn iso up to max for focussing

Actually, I'm not sure how a Bahtinov mask would work with your type of telescope. Maybe someone else will advise.

It's very difficult with such a small screen. You could use a Bahtinov mask to help you focus. Also, you could plug your camera into a laptop and use a program like APT (Astro Photography Tool) to enlarge the image you are seeing. https://astrophotography.app/ Where abouts in Europe are you, because if you are up North like me, it doesn't get fully dark in the summer. Also, it's a full moon tonight so you won't get good pictures of anything (except the moon) because of the moonlight.🙂

You won't know until you have tried it.🙂 City light pollution is a major nuisance. Most people use filters to mitigate it.

No, it wouldn't work with you setup. 😕 Never mind, for observing, that's really good instrument. I suppose you could get a camera mount and start with really wide angle shots with the DSLR and something like a fast 50mm lens. That would give you 6 second exposures. Then perhaps move up to a skytracker and longer lens when funds/inclination allows?

Ah no, that's a Dobsonian mount. I don't think you will be able to do it with that. For Astrophotography you would need an equatorial mount like the one on my 130p.

Yeah, a battery powered motor. I'm assuming you have an equatorial mount rather than an alt/az. It works ok. As I said, up to 20 seconds with a 200mm camera lens.

It looks like the stars are just trailing a bit. Maybe that is what DSS doesn't like. You could get a Right Ascension motor for your mount. I got one for my 130p setup before I realised the futility of imaging with it. Sky-Watcher RA Motor Drive for Starquest and AZ-EQ Avant Mounts | First Light Optics You could use it as a camera tracker (not man enough for the 130). You can't properly polar align with it but I have been able to get 20sec subs with a 200mm camera lens. I'm not recommending it as a good bit of kit but it is adequate enough for short exposures and isn't very expensive.

I think you will struggle to get star photos without tracking with a 130p. Using the '500 rule', your maximum exposure time without trailing stars is slightly less than .5 of a second assuming a focal length of 650mm.

I'm not sure whether it is possible to stack moon pictures on DSS. I'm sure someone will be along who can give an answer to that. What focal length have you got now that you have shortened your 130p? What ISO have you got set? 2 seconds seems like a long exposure for the moon.

It just raises the temperature enough to prevent dew forming on the lens. But I see you are using a 130p. I have one of those. Are you using a tracking mount? Do you need to use a barlow lens to get inward focus? 2 seconds is a very short exposure time. Also, in DSS, there is a function which allows you to select how many stars you want DSS to align. I think that if you set the number too high it will throw out frames with to few stars.

Yeah, I was scratching my head too for ages, as the subs looked ok - no visible star trailing, but just wouldn't stack. I don't know what kit you are using, how long your exposures are etc, so I can't really say why it isn't working for you. I bought a generic lens heater like this for about £20.00 off amazon. I power it with a USB battery brick. Since using it I haven't had the same issue with stacking.

Hi Lotinsh I had that happen with DSS a few times. I realised that it was that my data was no good and DSS couldn't match the frames. In my case it was twofold. Firstly, taking frames before it was properly dark, and secondly because my lens was affected by dew.

Pay day yesterday and that money is just burning a hole in my pocket 😰

As the others have said, the mount is by far the most important component for astrophotography. A skytracker/skyguider mount on a sturdy tripod will allow you wife to use an existing DSLR and lenses for astrophotography. Here are some examples which are within your budget and are available in the US: https://www.highpointscientific.com/telescope-accessories/mounts/telescope-mounts/ioptron-skytracker-pro-camera-tracker-mount-3322 https://www.highpointscientific.com/telescope-accessories/mounts/telescope-mounts/sky-watcher-star-adventurer-mini-pro-pack-s20582 https://www.highpointscientific.com/telescope-accessories/mounts/telescope-mounts/sky-watcher-star-adventurer-2i-pro-pack-s20512-1 https://www.highpointscientific.com/telescope-accessories/mounts/telescope-mounts/ioptron-skytracker-pro-camera-mount-with-ipolar-3322a