Aramcheck

You could think about getting an iPolar to help with the Polar alignment. I've found it very useful & quick to use:- https://youtu.be/4MXjN34Om_g Cheers Ivor

I've been wondering whether a barlow could be used with my SW200pds & DLSR, primarily for planetary & lunar imaging, but also for some of the smaller DSO's (with shorter exposure times to try to compensate for guide error). Does anybody have any experience using a one with this OTA? Currently with my DLSR the focus tube has to intrudes slightly into the OTA in order to get focus. I presume I would have to wind the focus tube out with a barlow? If it is possible to go down this route, any recommendations on a 2" barlow? Many thanks! Ivor

I'm mostly attempting imaging these days, but in the past we've found that the zoom eyepiece (a Baader Hyperion) useful as it saves having to keep swapping over eyepieces and filters. The main disadvantage, being rather short sighted, is that I have to keep removing my glasses to get the full FOV & my wife and I have to then refocus whenever we take turns at the eyepiece... Cheers Ivor

There are also Phone apps that allow more control over the camera settings (I'm not the person to ask though as I don't use a smart phone). Cheers Ivor

I use a 2nd hand astromodified 600d, purchased from Juan so +1 for advice given by @almcl. I'd also add to make sure the model will be compatible with APT. I found this site useful too, when picking the best ISO value to shoot with:- http://dslr-astrophotography.com/iso-values-canon-cameras/ Cheers Ivor

I read the other day that rather than recording say a 10min video, it's better to do 5x2min or 10x1min video's & then to use the free WinJupos software to help de-rotate the images:- https://www.skyatnightmagazine.com/astrophotography/astrophoto-tips/use-winjupos-derotate-planetary-images/ Cheers Ivor

I've also initially had trouble centering / locating objects. I found Astro Photography Tool (APT) to be a great help, as I'm no longer reliant on the camera live view. APT also has the advantage of being able to plate solve images & iteratively refine the mount position until the object is centered (or positioned wherever you want it to be)... For focusing, a Bahtinov mask (either made or bought) will help get precise focus, & here APT's Bahtinov Aid tool is useful too. If you find that you still can't get good polar alignment (or that it eats into imaging time too much), then have a look at something like the iPolar... Cheers Ivor PS: You're stars look nice & round which is a good start!

I believe in Stellarium you can use "Ctrl + 3" to sync the software, once you have found the target star in your finderscope & eyepiece. i.e. after polar alignment, you'd use Stellarium to go to a bright star, then use the EQMOD controls to reposition the target star in the fincerscope & then eyepiece, and then issue the "Ctrl + 3" command in Stellarium to sync position with the mount. I mostly use APT & platesolving as our scope has so far mainly been used for taking pictures... but in that too, after polar alignment I go to a bright star to set focus & sync the mount. Cheers Ivor

It's the product of three scripts in Pixinsight. First you run ImageSolver (Script->Image Analysis menu) to plate solve the image. Then run CopyCoordinates (Script->Utilities)... followed by AnnotateImage (Script->Render). The AnnotateImage script has an option for the PGC (Principal Galaxies Catalogue) and you can export a list to a text file. I usually then import the text file to Excel & look up the redshift radial velocities on Simbad. (From the radial velocity in km/s, divide by the Hubble Constant (68) to get the approx distance in MPc & then multiply by 3.26x10^6 to get approx distance in light years) I'm not sure if other Plate Solving software also has the PGC catalog (eg ASTAP, PlateSolve2 or All Sky Plate Solver). Cheers Ivor

Thanks @alacant. I haven't managed to get to grips with Deconvolution yet... Cheers Ivor

PIPP (Planetary Imaging PreProcessor) is a useful tool for centering images, prior to processing in Registax (or similar). Both programs are free:- https://sites.google.com/site/astropipp/home https://www.astronomie.be/registax/ Have fun! Cheers Ivor

Of course - no problem @alacant! If you'd prefer, have a play with a stacked but unprocessed TIF (I've saved as 16 bit to save space). Cheers Ivor M92_Int_16bit.zip

@StuartJPP Is it ok to share some of these with my colleagues in Leeds City Council & for a light pollution talk I've got scheduled? Also - could you give a rough time of night/morning? (& location) Excellent images BTW. Cheers Ivor

I had the same problem earlier this morning... but took the old school approach & copied the current RA/DEC position of Jupiter from Stellarium & then created a custom object in APT... I'll have to try the "Ctrl + 3" suggestion by @geordie85 as that will make life a lot easier! Cheers Ivor

I think it'll be too much magnification. The folks who've imaged it in our local soc have either used DLSR's with lenses & either single frames or on a tracking mount - or smart phones attached to binoculars.. It is quite bright (naked eye visible) and large, pretty much fills the view in 8x42 bins / 102mm refractor. I haven't managed to take any proper pics of it, other than with a Compact digital (non DLSR) on a fixed tripod. This is a 5 sec exposure from back garden early Sat. morning along with some Noctilucent clouds. Cheers Ivor

From early this morning... M92 in Hercules, taken whilst we were gawping at "C/2020 F3 Neowise" though bins. Lots of faint fuzzies in this one, although most don't have any Redshift (radial velocity) recorded on Simbad. Of those which are visible PGC2204313 is over 522 million light years away. (A Seyfert, PGC3096541 is given as 2.2 billion ly, but is too small to make out). Only got 24 usable subs out of 40 images due to guiding problems (& wind). SW 200dps + EQ6 + Canon 600d & 3min subs. At the end of the session I tried a 10min experiment to capture Jupiter using the DLSR live view & APT on 5x Zoom. Not wholly successful, but I'm not used to PIPP & Registax, so may not be processing correctly. In APT I unchecked "Live View Automation" (Tools->APT Settings) & set the APT camera settings to ISO 100 & 1/60 sec exposures. From the Planetary option in Tools menu I then used the option to save JPGs from the liveview stream. Gonna have to play around with things methinks... Cheers Ivor

I'm thinking of having a go at Jupiter or Saturn with the 600d & SW 200dps scope. What shutter speed & ISO would folks recommend for shooting in Manual Movie mode? Or is it better to use APT & capture the live view zoomed in x5? Many thanks! Ivor

So far £715 has been pledged against the £5k target required to force a judicial review, with just over 3 weeks to go. If successful it would pave the way to force councils to include appropriate measures against light pollution in planning applications, so I think it's worth supporting even though this action relates to Brighton. https://www.crowdjustice.com/case/put-that-light-out/ BTW - There is a study ongoing at the moment (https://www.sheffield.ac.uk/architecture/news/investigating-road-lighting-and-effects-safety) which hopefully will provide scientific evidence on road lighting requirements. The current BS standards are based on very limited (& flawed) empirical data, and if I remember correctly only suggest minimum lighting levels. On major roads, the standards are based on traffic flow rate, with brighter lighting specified at junctions & other collision zones. In Residential areas the specification as it stands is fixed, so there's nothing on making levels variable based on time of night. With insect numbers dropping 2.5% a year (a fall of about 70% over the last 30 years - partly due to light pollution), there is an urgent need for action. It's also possibly the only environmental problem that can be solved literally by the flick of a switch... Cheers Ivor

Pixinsight's "StarAlignment" process will cope with images from different days & orientations (eg flipped 180 deg), or if some subs are binned and others aren't. It is however best to only run StarAlignment once & then to integrate the subs. If need be you can manually align individual images using the DynamicAlignment tool, or run StarAlignment on your new subs using the same Reference image as you used originally. Cheers Ivor

With the Canon 5D MkIII it looks like you could get away with ISO1600 (or possibly 3200), judging by the dynamic range curve: http://dslr-astrophotography.com/iso-values-canon-cameras/ You could also try controlling the camera with Astro Photography Tool (APT) in case you're not getting good focus. (If you can, use a Bahtinov mask) As @PeterCPC says, the mount is not well suited for DSO imaging, so you'll have to experiment to see how long you can make exposures with acceptable star trailing. I don't think anything can be done about field rotation though. Apart from the additional read noise & processing time, you should be able to reduce the individual exposure time & compensate by taking more subs. Cheers Ivor

You can also control the Canon EOS 600d with Astro Photography Tool, running on a laptop. You just need to set the camera to manual mode & connect with a USB lead. All the settings for ISO / exposure are then taken from APT & the image is displayed nice & big on the laptop screen, with the ability to zoom in (& platesolve if you wish). The software also has a neat Bahtinov mask Aid tool too. https://www.astrophotography.app/ Cheers ivor

You can think of the light pollution signal as being added to the light that you're trying to capture, so to remove it you need to subtract the light gradient from the image. How you subtract the gradient will depend on the processing software you use. You can mimick the gradient using a gradient tool, or create a blurred copy of the layer in GIMP, & subtract that - or in Photoshop there's also a Gradient Xterminator plug in. @alacant has posted some great images using the free Siril software to remove light gradients & APP/StarTools also have processes to remove light pollution. I prefer Pixinsight, but am not as adept at using it as a lot of folk & I could only do limited processing on your pic, as it was difficult to find areas without stars & I wasn't sure where the nebulosity was supposed to be. In Pixinsight the process used is called Dynamic Background Extraction (DBE), where you pick points in the image to model the background & then either subtract or divide from the main image. (Division is used where there are multiplicative effects from scope vignetting). I also took liberty to plug the (partially processed) image into Astrometry.net. http://nova.astrometry.net/user_images/3798032#annotated Cheers Ivor

I think you'll need to provide the stacked but unstretched image of the RAW files, as this one has already been stretched. You would normally try to removed the light pollution background whilst the data was still in it's linear (unstretched) form. It's always better to have more exposures (and/or longer exposures if the mount tracking will allow). Also how dark was the sky? At the moment here in the UK there is only a small window of Nautical Darkness & where I am it never reaches 'Astro darkness' at the moment. If the DLSR is un-modified that will also affect how much nebulosity you can capture, but that will vary between targets. Cheers Ivor

the 4th edition was published in 2014. The 3rd was originally published in 1991 but has been revised since. Mine was printed 2005. As most stars don't move that much relative to each other I'm happy with the older version. Cheers Ivor PS mine is the hardback, which isn't as useful at the eyepiece, but each page has more sky on it than the Pocket Atlas, which can be advantageous...

I've got both the "Cambridge Star Atlas" (3rd edition) & "Sky & Telescope's Pocket Sky Atlas". The latter is ring bound & smaller, so I've found it more useful when I'm out at night with binoculars. It doesn't have as many stars plotted as the hard bound Cambridge Star Atlas, but does have constellation lines marked. I like both though & you can pick up a 3rd edition copy of the Cambridge Star Atlas very cheaply. Cheers Ivor