Gfamily

That's very good - I'll share it with our Astro Club at our next meeting. There's a nice comparison you can make to pass on the insane scale of the Universe - that if you put the Earth-Sun distance at one inch, then one light year is a mile. So the nearest star is 4.2 miles away. Useful to have in your mind something that's about that distance that will be meaningful to your audience.

At present, I don't know what I mean by 'small' either - I may get to see it sometime in the next week or so. It's described as 'smaller than this' --> but we'll see.

I know somewhere that has a small plastic observatory dome that isn't in use, and might be available if someone can take it away. I don't know the size or the state it's in, but I'd be interested to know whether people actually find them useful - or is the space inside too limited to make for easy use? Anyone here with experience of a small dome, and what's your view?

Very surprised to see a clear blue sky this morning, as the forecast had been for cloud all day. Quickly set up the small refractor to track, and did some visual observing and then some imaging. We'd ordered a set of eclipse glasses from Neill at GoStargazing, so went over to our local supermarket carpark and caught people as they were going in and out. About 30 people in total, most of whom had no idea it was happening, and were mostly very delighted. Might even have a new person for our astronomy society as a result.

Very similar to everyone else, imaging the eclipse.

A quick search through Google Books for content that included the words << narrowband, filter, astronomy, amateur >> for books from the 20th Century brings back snippets of text from some older books. The earliest reference from 1972 relates to the ability of amateurs to use a Narrowband Solar filter for observing Solar Prominences since about 1967 The use for Solar observing is also mentioned in the 1986 Yearbook of Astronomy For non solar work (adding OIII to the search) the references seem to come later - with a mention made in a 1994 issue of Astronomy Now magazine.

There's a Heritage 130P currently on Gumtree for £120 - if you're near Derby. Also a 100P Heritage in South Shields for £90 They may already have gone of course.

No, no, no. Clearly someone who has no experience of the Heritage range of scopes. And anyone who seriously thinks that showing someone a simulation on a TV screen will satisfy an interested child probably has no experience of interested children either. Does this person even enjoy astronomy themselves? "Look at it on a TV screen indoors" - what sort of astronomy is this? * Going back to the original request - I can see why people might recommend binoculars, but bear in mind the following Children often find it not at all easy to use adult binoculars, as they need to set the correct spacing between the eyepieces Children can also find it difficult to manage getting the right dioptre adjustment setting so that both eyes are focussed together Adults can find it tiring to hold binoculars for a longish look at high altitudes, and children will tire even earlier. And again, as someone has pointed out - if a child wants a telescope, they'll want to feel they have a telescope, and not been given a substitute. If you already have a reasonably solid camera tripod (or can get one second hand cheaply), a short refractor may well fall within your budget - I was quite surprised by how good a view I got from the Celstron Travelscope70 when I bought one for my nephews. It did need a better tripod than the one provided, but the telescope was pretty good for the money, and easy for the boys to use with minimal adult help. But the best option would be the Heritage 130P if you can get one second hand (try Gumtree or eBay) * My little joke, clearly these are imagers!

I don't think so, as there are some bright stars visible with prominent spikes. Interestingly, there is a HST image also in the IR which shows the same stars not visble in the Visible (as it were). You can tell it's a HST image as it has the four spikes rather than six. ETA - @robin_astro beat me to it.

I guess appearances are deceptive...

They'll be stars that have had their visible light blocked by dust.

If not this one, it'll be a similar one https://spacenews.com/nasa-outlines-case-for-making-sole-source-sls-award-to-boeing-northrop-joint-venture/

My only real planetary image was captured using a modified £2 webcam using Sharpcap After an initial process in Registax, an astro club colleague suggested I try processing in AS!3. Following the initial stack, I then dropped it into Registax and applied the same wavelets as before.

What I find interesting, is not just the rings, but the additional rays towards top-right, bottom-left and also top-left. They look almost like diffraction spikes, so I'd be interested to know what happens if the 'known' SPF is subtracted.

Good suggestions, above - though I would warn that the Double Cluster in a Mak is likely to be the Cluster and a Half 😀, as the field of view is relatively small. As suggested, double stars can be good targets - Mizar and Alcor in Ursa Major is good, and Albireo in Cygnus is excellent. You can also try for some Globular Clusters - M13 in Hercules is good as it's easy to locate ( 1/3 down the right hand side of the Keystone) and also easy to identify because of the two stars with which it makes a triangle. Dark skies will always help - particularly for larger, more diffuse objects and I'd suggest getting a nice low power eyepiece as it should help with the contrast for these things.

In case anyone is interested in why a head on collision seems to have made Dimorphos orbit Didymos quicker (rather than slowing it down).

According to a tweet from someone following the press conference, the orbital period has changed from 11h55m to 11h23m - which is 'apparently' about a 3x greater change than expected. So - worth doing.

Well, it was pretty much clouded out here, and the Moon wouldn't have helped. Another look at the lunar calendar app advises that there will be a waxing gibbous moon on 5th November (as well as lots of fireworks and smoke here in UK), so maybe a better day will be towards the end of November, on 22/23rd - there be a minimum just after midnight on 23rd, and a New Moon later on the same day.

Oh no, how disappointing. I don't know whether there are any UK companies that can offer a replacement service. A quick google suggests that Grover Optics offer a replacement for the Celestron 8" SCT, and as the UK agent for Celestron, they may be able to help with yours.

The eclipsing variable star Algol takes about 9 hours to complete the eclipse process from initial brightness, through the dip, and recovery to full brightness. WIth a period that's about 3hours and 20 minutes less than 3 days, it can be tricky to get a timing when both the max and minimum brightness can be seen on the same evening - at least without having to wait up until the early hours. However, this evening (10th to 11th October), there will be a minimum at 1am BST, so it may be possible to have a look at about 8pm, and then have another look at midnight. The magnitude should drop from 2.1 earlier in the evening to 3.4 by 1 am. To compare the brightness - the Sky at Night website suggests Gamma Andromedae (2.1) and Epsilon Persei (2.9) as both are relatively close-by. Alternatively, the two stars at each end of the W of Cassiopeia are similar magnitudes to the Max and Min (Caph at 2.2, and Segin at 3.3 respectively) . https://skyandtelescope.org/observing/the-minima-of-algol/ Unfortunately, the nearby not-long-past Full Moon won't help. If tonight isn't good, another good chance might be on 5th November, when minimum will be at about 7:20pm, and full brightness should be restored by midnight.

You can DIY one using an A5 sheet of Baader film. I cut strips of card to fit around the OTA, and use double sided tape to hold the Baader film in place. Cut a circle of film about 2cm larger than your aperture, and cut 'petals' for the outer 1cm all round. First strip of card snugly around the OTA Put a strip of double sided tape right around the card. Put the Baader film across the aperture and push down the petals so they stick to the card. The Baader film shouldn't be pulled too taut - it's not meant to be like a drum. Then another strip of double sided tape, and then the second strip of card. The whole filter assembly should then fit snugly and securely over the objective. If you have a finder scope, remove it, or make a similar filter for the finder's objective as well.

It is possible that the need to re-focus is exacerbated for astronomical observations because the iris is wider at when you are making nighttime observations compared to your iris size when birding during the day. Have you tried using the Travelscope at night, to see if the 'no need to refocus' applies there as well? It is also possible that for some reason when you use the Travelscope for birding, you are automatically putting the final image at a virtual position that is within the accommodation distance for your uncorrected vision.

It seems the real 'irreplaceable' aspect is the ability to image in the UV - HST's performance in optical wavelengths can be pretty well matched using ground based adaptive optics, but its UV capability is not going to be matched until the deployment of the LUVOIR major space telescope in 2039. It would be interesting to see whether a combined power - stabilisation unit could be clamped to the HST to replace the functionality of the failing/failed inertial wheels. An interesting question is whether the torque dumping capability (in part currently done by interaction with the Earth's magnetic field) would continue to be effective if it was boosted to a significantly higher altitude. Well, I have no doubt that it could be replicated, but it is an additional factor to contribute to the complexity

However, any dark matter particles that are on a trajectory that passes through the cross section of the Black Hole will be absorbed into it, so the mass of the BH will increase over time, should there be a steady stream of DM impacting on it. There is a suggestion that although DM particles don't interact with Standard Model matter, they may interact with each other - and this modifies the distribution of DM particles around galaxies (the observed distribution doesn't seem to follow what would be expected if there was NO self interaction, so it proposed that there is SOME interaction, albeit not one one that is understood).

I use a diagonal, so it's always seen with the two eyes at the bottom - it's clearly a dragonfly. Two huge eyes, four wings . A dragonfly.