Gfamily

The 150p Heritage Skywatcher is a collapsible Dob. With a small camping table it's quick and easy to set up and use.

Yes indeed NGC457 is a great cluster. The telescopes I started with were Maks and SCTs, so I missed out on the delights of many open clusters. I have a particular affinity for NGC457 as it was one of the first OCs I look at with a short ED refractor that I had borrowed while staying at Astrofarm France. I was using the scope on my GTi mount and one of the "Tonights Best" was the Dragonfly Cluster - not one I was familiar with. Under the dark sky with a crisp contrasty scope it was a real delight, easily visible as a dragonfly, and as it was rising at the time, with the diagonal I was using it looked like a dragonfly as opposed to an upside down Owl or ET. "Ah, so that's why people like refractors" was my take-away thought

I don't know where they got their estimate for the kennel though, as it seems to have gone for only about a quarter of what they were expecting.

What I think it does is give the time that the Moon would rise if the moon was at the position it is at at 00h00m00s on the date given. If you check with Stellarium it does much the same thing, so that it gives different rising times depending on whether you ask for the rising time at 0h, 12 h or 23h

One way of reducing the thermals when settling up is to insulate the scope. It sounds counterintuitive, but it's the rate of temperature change that causes the thermals, so wrapping the scope in a couple of layers of radiator foil can slow this down and make the scope usable almost straight away when setting up.

You may be aware that the name Pluto was suggested by an 11 year old English girl called Venetia Burney, after her grandfather pointed out the newspaper article about its discovery. As it happens, her great uncle had suggested the names Phobos and Deimos for the moons of Mars.

Without wishing to diss your approach; I used a sheet of Proplex (box-wall sheets used as temporary floor cover by builders), which can be bought for about £5 for a 1200x2400mm sheet from Wickes DIY shops over here. Cut a suitable length / width and used sticky Velcro pads to hold hold the bits around the OTA. Folds flat, so even less volume than a foam mat, and the Velcro sticks pretty well to the plastic so less need for jabbiness. You could probably do half your astro society members' scopes with one sheet.

Yes, working now. Thanks

Thanks John It mostly works, though the links on the 'grubb-parson/documents' page https://sites.google.com/site/grubbparsons/home/grubb-parsons/documents Show as "Google Drive - you need access " messages

Illuminated by starlight! Amazing. And here's the initial configuration mosaic image showing the 18 individual element images

It's unfortunate that is not on Android, as I'd really want to try it out. The science content is provided by Dr Jen Millard, who also contributes to the Awesome Astronomy podcast as well as often appearing on the TV and radio when someone is needed to talk about astronomy matters. If anyone's been to Astrocamp they'll know Jen.

The Wayback Machine seems to have archived a copy from 2014 - there may well be later copies. https://web.archive.org/web/20140320080000/https://sites.google.com/site/grubbparsons/home

As their aim is to get a distribution of different orbits to ensure their constellation has a comprehensive coverage, I speculate that having a launch to an initial low orbit with an extended period of adjustment makes it easier to get a wider variety of final orbital elements, and maybe an initial deployment to a higher orbit would make that more difficult given that each launch releases upwards of 50 satellites at a time. This is pure speculation mind - though we know that SpaceX do seem to be remarkably effective at producing efficient solutions to whatever they see as being needed, so I assume there's a good reason. Though why they thought it a good idea to launch just the day after an M class flare hit the Earth's atmosphere is a good question.

Dangerous irony there (I hope).

Yes, loosen the collar and the whole front of the finder holding the objective is on its own (internal) thread so it can be adjusted.

Just to clarify, focus is adjusted by loosening the large locking collar towards the objective end of the finder. The objective lens can then be screwed forwards and backwards to set the focus. When good focus has been reached, tighten the locking collar and it'll hold. As others have said, if the adjustment screws don't allow you to get good position on the cross hairs, then it's best adjusted by means of the finder mount in its shoe. ETA, sometimes you need to adjust the position of the rubber ring around the finder, so it's centred within the mount.

If the SQM reading is based on astronomical magnitude, a difference of 1 represents a 2.512 difference - as 5 magnitudes represents a 100 fold difference in brightness.

The diary for talks says that Paul Money will be giving the first talk at 9:30 in the morning The last talk is Damian Peach's, which ends at 4:10 in the afternoon. https://practicalastroshow.com/speakers/ Hope this helps.

This year would be getting my very own Lightwave 72mm ED-R - having had one on loan, getting one on ebay was a great find. If this thread had existed for 2020, it would have been Mrs Gfamily and myself simultaneously seeing a Perseid pass right next to M22 through eyepieces. I was using a low power refractor, while she was using a pair of binoculars. Seeing any meteor pass through an eyepiece view is unusual for me, but for us both to be looking at the same target at the exact moment was a supreme coincidence.

Throwing straight up isn't going to put things into orbit, the direction's all wrong. Also, what are the G-forces involved in that?

Poundland have done spring loaded clamps that fit onto a mini tripod. The mini tripods are pathetic, but the thread used to mate with the clamp is a standard 1/4" thread that should fit a standard camera tripod head

The initial positioning of the mirror segments means that each one is going to be producing its own image and these are going to be fairly randomly distributed about the nominal centre of the field of view. The initial activity will be to produce a mosaic covering an area of 24' by 25' (600 arc minutes). This will require about 100 separate images being captured by the one of the NIRCam imager sensors. If not all 18 segment images are captured in this initial mosaic, more frames will be added to widen the field. When the locations of the 18 image components are known, the next process will be to identify which mirror component relates to which image and this will be done by centering on the image and giving each mirror segment "a little pirouette" - when the image moves, they'll know which mirror produces it. When the images from all the mirrors have been identified, the mirrors are moved to bring all images together into a hexagonal pattern within the 3' by 3' field of view of one of the NIRCam sensors. A combination of focusing and de-focusing of the individual images allows waveform calculations to be made to allow the precise configuration of each of the primary mirror segments AND the secondary mirror to be determined There are 131 distinct adjustments available on the Primary Mirror segments, and 113 distinct adjustment modes available to the Secondary. One issue is that there are multiple sensors that occupy different areas of the overall image field of the telescope - so the focus has to be optimised not just for the 3' x 3' field of NIRCam, but across the wider area so that data can be captured for MIRI, NIRSpec, NIRISS and the Fine Guidance Systems (FGS) A summary is here https://www.spacefoundation.org/wp-content/uploads/2019/07/Acton-Scott_WAVEFRONT-SENSING-AND-CONTROL-FOR-THE-JAMES-WEBB-SPACE-TELESCOPE.pdf Thanks due to Mark McCaughrean at ESA (on twitter) for pointing me in the direction of this data

+1 for this.

It has options for Sidereal tracking, Lunar tracking and no tracking. You can download a Windows version of the App and experiment with the options. You can also do this on a phone, but if your phone is Android 11 you'll need to get it from the Skywatcher Website rather than from Google Play Store. It's a very nice piece of kit

There's a Facebook group that gives heads up of when the booking opens. The dates for the next few have been announced Next September 24 - 27 Following April 22 - 25 September '23 16 - 19 More generally, the gostargazing.co.uk website holds details of Astro Events across the country