callump

I get the digital Sky & Tel - it has been improving over the recent years, and in the Jan 2021 issue an excellent article on winter galaxy groups. The price increase was a shock - but then it's only the price of two or three coffees (or one beer in some London pubs), so I will be continuing my subscription. I also get Astro Technology Today - it is really good. And Amateur Astronomy Magazine - which also has good content. /callump

I'm not familiar with the 6 SE, but the Celestron 0.63 FR has a working distance of 105mm - that is the distance from the back glass element of the FR to the front of the sensor. I think putting the Crayford after the FR would allow you to change the working distance but not the focus. So you would need to put the Crayford onto the scope, then the FR, and then a spacer to get to 105mm. I don't know if you would get sufficient back focus though. /callump

Thanks for all the comments and thoughts folk. I've upgraded my iMac and not found any problems so far... My son upgraded his MacBook Air ok - but seems slow. I think i'll wait a little while before i upgrade my MacBook Air (which is what I use in the observatory). Callum

I made my own Bahtinov mask at virtually zero cost - works fine... /callump

Some people are using Open Broadcast Studio to aggregate their sources (video, audio, windows, etc). In it you can setup a Virtual Video Camera, and then feed that into Zoom or Facebook live as the video source. There are lots of options and seems to work well, and is free. Callum

Just wondering if any MacOS folk have updated to Big Sur from Calalina? And if so, what experience of astro application compatibility. Hopefully it will all go swimmingly, but I may wait a few weeks to see if there is any fall-out. Callum

This weeks British Astronomical Association Wednesday webinar is on Video meteor detection and spectroscopy. Wed 11 Nov at 7pm GMT. You can view on Zoom or YouTube. Open to all. Full details at: https://britastro.org/node/24212 Enjoy... /callump

Hi Mike, what sort of Dob and drive system do you have? Thanks, Callum

It comes to opposition on Nov 6, and does have outbursts - so always good to monitor it. At the BAA meeting yesterday, Nick James mentioned it, and apparently it is one of the biggest comet nucleus' at about 60km. Callum

Looking for a patch of sky which looked better than most, I headed to Cygnus, which was setting to the west. Although over my neighbours house, I don't have too bad an outlook that way, with no major light polluting towns. Here is NGC 6946, the Fireworks Galaxy. There have been a few supernova discovered in it over the years, but I have not checked this image (yet!). Thought there are a lot of field stars in the area which makes checking tricky. Framed to try and avoid the dust-bunny...

Here is ARP 282 from last night. Comprising NGC 169 and IC 1559. Also in field NGC 160 to right, and UGC 354 above. Not great sky conditions in that area of the sky for me last night. Callum

To continue a Variable Nebula theme, here is Hinds Nebula, NGC 1555, in Taurus. It is associated with the variable star T Tauri. I think that the VNe nebulae are generally dust and gas in the region where the star formed rather than being thrown off the star. The illuminating stars tend to be quite young stars. There are just a few known VNe, and a couple of these have currently disappeared - NcNeil's near M78 in 2018 (still not visible), and Gyulbudaghian's (associated with PV Cep). The areas are worth visiting from time to time in case they burst into life again. The BAA has a programme monitoring these, and there are interesting observations over many years. Last night was clearish, but not the best of skies. This was late on (for me, on a work week). I've changed to a Celestron focal reducer (f6.3), which seems to be better across the field compared to my old clone. Measured focal ratio is f/6.1. Horrible dust bunny appeared though annoyingly in the middle of the field - will need to hunt that down over full moon. Callum

i have the desk edition of the Interstellarum Deep Sky Atlas -and it is my 'goto' atlas these days. The page organisation and the way it has been annotated make it a joy to use. I use it mainly for building observing lists, and don't take it out the field. I have a fair few number of atlases, but none other makes it off the shelf these days, except on occasions my Pocket Sky Atlas or 1950's epoch Notron's. Callum

Sorry, yes you are right (though I am sure when I last looked for one there was - but that may be several years ago). I guess more accurate to say client neutral. I expect most INDI users use some sort of appliance on the telescope, and whatever client platform of preference. Alpaca will no doubt provide a practical similar solution some time in the future... Callum

People might find this YouTube video of Bob Denny (one of the Ascom/Alpaca driving forces) useful - especially if you know nothing about Ascom or Alpaca. https://www.youtube.com/watch?v=Qd1ZsJ_Q1XY Its a while since I watched it, but I think the essence is that Alpaca is not really there yet... And whether it ever will be is moot - it may get somewhere, but will never have complete cross platform support. At the moment I think INDI is the only complete cross platform that actually works. INDIGO is good if you want to use Cloudmakers apps, and it also falls back to INDI too but there's not much in the the way of third party clients. Callum

There is a table in the Astrometry.net README that gives the range of the skymarks for each set of index files. If you know the size of your field, you can just use the height in arc-minutes to work out a range of index files you need. E.g. for a 30 arc-minute image you might want to use: index-4205-*.fits 11–16 index-4204-*.fits 8–11 index-4203-*.fits 5.6–8.0 index-4202-*.fits 4.0–5.6 /callump

The renowned American astrophotographer Adam Block will be presenting at this weeks BAA Wednesday Webinar, on the "Interpretation of astronomical images". Adan is an astronomy researcher at the Steward Observatory, Arizona, and was the founder of the stargazing programmes at UA Science Mount Lemmon SkyCenter. He had a regular column in Astronomy magazine, and his images frequently appear in the astronomical press. He has several APODs to his name, the most recent being May 11th 2020- Behind Betelgeuse. You can view many of his splendid images at: https://www.adamblockphotos.com The webinar starts at 7pm. Open to all - Zoom and YouTube links at: https://britastro.org/node/24212 Callum

The problem with Preview seems to be something to do with the MacOS quarantine system. All the files downloaded have an extended attribute marking them as quarantined. You can remove the quarantine attribute - but I found that even if you do that it comes back as soon as you select a link in the PDF. I tried a few things (like making the files read-only, owned by root, even re-writing the files using Ghostscript) but none of these seemed to help. Possibly you have to downgrade much of the MacOS security subsystem to get this to work with Preview - so it seems easier just to use Acrobat. Callum

I'd say reduce the length of the PFTE pads - the more surface area in contact the more stiction. Once smaller, you can also adjust the position of the pads to achieve a nice feel. Looking good - nice to see the old scope 'reborn'! Callum

This weeks BAA webinar is on observing occultations with Tim Haymes, from the BAA Asteroids and Remote Planets Section. Wednesday, 30th September at 7pm. You can join via Zoom or watch on YouTube. Open to all - details at: https://britastro.org/node/24212 Look forward to seeing you there. /callump

Hi Toedeh, I started with an ASI290MM mini camera for EEVA as it was what I had (i'd bought it for guiding). Here is a pic I took with it of M82 - this was my first go at EEVA so did not know what I was doing at all! The tech details are: Celestron C11 with F6.3 reducer Losmandy G11 mount ZWO ASI 290MM Mini camera Indigosky Raspberry Pi Cloudmakers Astroimager and Astrotelescope Processing using Jocular Stack of 10 sub-exposures of 10s The ASI290 has quite small pixels - 2.9 microns - and the chip is quite small, so after much deliberation & dithering and in the end not really being able to decide, i plumped for an ASI174MM mini. Which has bigger 5.8 micron pixels and a bigger chip (so able to get a wider field). Here is a pic of NGC 891 I took recently with the ASI174. M82 is about 9 arc-minutes long, and NGC 891 is about 13 arc-minutes long. I have cropped the NGC 891 image square to be about 14 x 14 arc mins in size, as I am currently getting awful edge effects. I'm not sure it will help your decision process really - it is worth trying out field calculators to see how big a field you will get with whatever scope and camera combinations you like, and what sort of objects you are interested in observing. Also to some extent it will depend on how much you want to pay for the camera. Callum

I like a diffraction spike when it is a real diffraction spike (like here!) Callum

You could try Cloudmakers Astroimager http://www.cloudmakers.eu/astroimager/ which is a native MacOS app. It supports the Altair cameras but probably in the same way as INDI so might not recognise the camera if the problem is with the Altair driver. There is a free 1 month trial. Version 3 is currently the one that downloads, but there is a development version V4 available that does live stacking and sequencing (I have not tried it at the telescope yet, though). Callum

Hi Martin, internet images show the nebula as mostly blue - i guess it is fairly old. Your blue central star looks like a good candidate for the central star! There is a PN Jones-Emberson 1 which is in Lynx - looks like a good target too, when it comes round. Callum

Last night (2020-09-20) was not the clearest of skies, but I managed to capture a few galaxies. NGC 404 - AKA Mirach's Ghost - was actually easier than I had expected... NGC 891 - the Silver Sliver galaxy NGC 507 and NGC 507 Group of Galaxies V V 209 With the astrometry.net annotated view. Finally an oddity, marked on the Interstellarum Deep Sky Atlas - Barbon's Galaxy. Discovered by Roberto Barbon in the late 1960's i think. It was highlighted to him as a faint smudge on a plate - Barbon took a spectrum to reveal it as a galaxy. It is a Blue Compact Galaxy - if the conditions had been better I might have tried an LRGB to see if it had a blue excess. Callum