Annehouw

+1 for the PoleMaster. I had it on my Astrotrac, which is a capable tracker and to get great results you need an accurate polar alignment. I bought the polarscope and let's say it was less than optimal.... With the Polemaster, you can have your rig polar aligned withing 5 minutes after your first sighting of Polaris and have a few cups of coffee before astro darkness. I now use this same Polemaster on my iEQ30Pro. I use it with a laptop, but there is an Android version of the SW as well. Having said that, iPolar and Sharpcap will work too. For my permanent set-up in the backyard, I do a traditional drift align. But that is only needed once every year or two years.

Jarvo, If you can guide, you can dither. It is done in software and works fine through the ST4 connection. If you use PHD2 you can set the dither scale (in guide camera pixels). Now, as dithering has to be performed between exposures, the triggering of the dither will be done by the acquisition software. I use APT (astrophotography tool). You tell it how often you want to dither and off you go. Other software (like NINA) works about the same.

The power of dark skies and fast optics I am going through some files on my hard drive. Two years ago I made a trip to La Palma with a rented Canon 300mm f/2.8 lens, a star tracker (Astrotrac) a dslr and a intervalometer. This is one of the images as a result. The lens was used wide open. The camera was a Canon 5ds. 50 megapixels per shot (which is nice and the Astrotrac could handle that unguided for up to two minutes), but a lot of banding noise and not very sensitive to red. 40 times 90 seconds exposure at iso 1600. For the record: This lens (wide open) has "dark lighthouse beam" artefacts on stars. I have corrected it for Rigel as I found it distracting. All the other stars still have this artefact (e.g. lop left). I certainly will return to La Palma when the situation normalises.

@Carole: Thank you very much! @Taman: Thanks for the suggestion. However, my industrial design skills leave much to be desired......😬

Thanks, Knight of Clear Skies I do not want to rain on my own parade, but unfortunately what you are seeing at the 5 o' clock position are two galaxies. The jet should be at the one o' clock position and whitish in color. As you say, it is best imaged with short exposures. Maybe next season with a bigger scope....

Thanks, Mark Forgetting things like Tak, TEC, AP, PE, Strehl ratio, etc, there is a lot to see here. E.g: Galaxies in the Markarian's chain are part of the Virgo supercluster, as is our Milky Way. From the Arp catalogue, there is: Arp 120 (Copeland's Eyes), a galaxy merger in progress. Arp 76 (M90 and IC 3583). This close pair of galaxies are separating fast and M90 is one of the few galaxies that has a negative redshift (i.e. it is coming towards us). Then there is M89 with surrounding shells and a plume that is ejected Last but not least there is M87 with the famous jet and even more famous this is where the Event Horizon Telescope last year imaged the accretion disk of a massive black hole. Now look again at the picture as a whole and think of what you are actually seeing. To quote a well known pointy eared scientist: Fascinating! 😉

Nice! You even got the dust clouds in M110!

This 2 pane mosaic was the first outing of my FrankenOptics scope on a iEQ30 mount and also my first mosaic. There maybe some interesting learnings for others, so I will describe my experiences in making this image a little bit: -The refractor is a collection of pieces screwed together with tape in two places. The objective cell is a William Optics 80mm f/6.9 FD ApoGrade. This is an upgrade that was sold many years ago by William Optics to convert a semi-APO Megrez 80SD into an APO refractor (Megrez 80FD). The tube is not original, the focuser had variable slack, and the original focal reducer/flattener was OK at the time for tiny sensors, but not for my current APS-C camera (QHY168C). So, I bought a "cheap" focuser (GSO linear) and a not so cheap WO 6AIII reducer/flattener. Long story short, I was not able to completely eliminate tilt and curvature, but enough to my liking (and patience). I taped both the focuser and the variable ring reducer, so I would not inadvertently mess up with the alignment during transportation. There is color fringing in this scope, but it is not that bad (it still is a doublet). So much for the eccentric bit. -The iOptron iEQ30 that I had bought second hand last year turned out to have a periodic error of 60 arc seconds (peak to peak) and at some points a bit steep. I had 4 clear nights in a row for making this image. The first night I could not guide better than 2.5 arcsecond RMS in PHD2 (elongated stars). My image scale is 2.2 arcseconds, so this is not good enough. I improved on this every night until I got to 1.2 arcsecond RMS the last night. Not stellar, but just enough for this image scale. The trick that did it for me was using the Predictive PEC guiding in PHD2, combined with short (1sec) guide exposures. There was also quite a bit of DEC backlash, but that was manageble. I have found some tuning tips for it's big brother, the iEQ45, so I might give that a try in the summer months. - I used a ZWO290 camera as my guide scope and once I changed the driver from ZWO native to ASCOM in PHD2, typical snr skyrocketed from 15-20 to almost 200. The image shapes changed from spikes above a noise floor to nicely formed bell shapes with a nice peak. Strange but true. - I planned the panes in telescopius.com and that worked very good! - Both panes were pre-processed separately in AstroPixelProcessor. Generating the mosaic was a non-event. I followed the guide of the tooltips and it worked on the first try. - Because my wrestling with guiding, the stars are not really round, but because it is a mosaic, it does not show that much. - Post-processed in PixInsight with a final touch in Photoshop CS6 There is a larger version here: https://www.astrobin.com/mgo1hr/ with acquisition details and a mouse over shows a great many galaxies in this image. CS, Anne

That is a nice image! I agree with the comments on the noise reduction but the unevenness of the background brings up an interesting question. Point is that there is quite some IFN in the area as can be seen here: https://www.astrobin.com/316608/ (not my image). It brings up an artistic question whether you want to show that or even put emphasis in the IFN. Most people (including me) tend to darken the background and kill the IFN (for the most part). In telling a visual story, there needs to be a subject that is recognisable. And sometimes leaving elements out (in this case IFN, but it can also be through cropping) gives a stronger composition and a clearer image. I have seen imagers presenting images where there is a mist of IFN with some galaxies shining through. A valid artistic decision of course, but I generally am not in love with those images. Now, if we are talking of dusty regions in the milky way, like the Iris Nebula..then yes. I love the whisps of chocolate coloured dust clouds. Just an opinion, of course....

With Lorenzo coming our way, this may take some time. You can test it on an existing image in the mean time. Here is a complete guide: http://aptforum.com/phpbb/viewtopic.php?f=24&t=474

I had the exact same issue. After I changed the Max Star Size parameter in ps2 from 6 to something higher (I chose 12 after examening the star recognition image...at 6 a lot of bright stars were not taken into the platesolve pattern), it has been quick and reliable.

Late summer brings a lot of clear skies here in The Netherlands. After that the stormy season starts to spoil a lot of the fun. The RGB (OSC) images were all unguided 90 second exposures. I am a firm believer in dithering, but with my scope, using PHD2, this takes a minimum of 60 seconds per dither, which makes it not very efficient. Luckily Astro Photography Tool has a dithering algorithm without the need for guiding, so I used that. It is very, very fast. Ha signal was aquired with the same (QHY168C) camera using the STC DUO filter. This time with 360 seconds guided sub exposures (and dithering in PHD2). Scope used was my backyard stationed 320mm f/3 hypergraph. Stars tend to saturate real quick with this setup, so I had to work quite hard to keep the stars small. The total integration time was about 16 hours. The subjects are not very faint, but with my Bortle 5 skies, I need a lot of integration time to bring out the objects in a nice way. Software used: APT for acquisition, Astropixelprocessor for calibration, integration and registration, PixInsight for most of the postprocessing, Photoshop CS6 for the finishing touches. More details and a larger version here: https://www.astrobin.com/qehqch/

I now see that I could have said: What symmetal said......

Hi Alan, Do both. Really. I use a QHY168C which uses the same IMX071 chip as your ZWO071. - It has no amp glow (not my camera at least). The rest of the pre-processing frankly is the same as with CCD: - Use a fair amount of dithering (every 2-3 exposures) to combat fixed pattern noise and help the statistical outlier rejection algorithms in the software of your choice (I use AstroPixelProcessor and it is a brilliant and very user friendly piece of software). - Dark frames are fast and easy, why not use them as well?: I have a library for my 2 exposure settings (50sec for L, 300sec for narrowband). Darkframes for summer (-10C or -15C) and for winter (-20C). Do an average of 30 darkframes, make a master dark. You can use those masters easily for a year. - Generate a bad pixel map (of a defect map) in your software of choice. Again..can be reused for at least a year. - No bias needed if you use master darks with the same exposure time at the same temperature as the exposures. Working with a temperature regulated camera is convenient and efficient compared to a dslr where you have to scale darkframes due to temperature fluctuations. Regards, Anne

Hello John, No 😉 But you are completely right there is not that much of a difference in noise between -10 and -15 or -20. But since we are trying to separate tiny amounts of signal above the noise floor and my camera is specified for -35 below ambient and easily does -40 in practice I have standardized on -20 degrees below zero. Here in NL the summer is lousy for imaging anyway so this is fine for 90% of the imaging season. Malta is a bit warmer, even in winter. Lucky you!

Definitively less mosquitoes at -20......

Here in The Netherlands it only gets dark again around the first of August. Often the skies are clear at night. Only this year daytime temperature was almost 40 degrees and we had above 20 degrees at night. As a result, I could only cool my sensor to -10 degrees, but the results were OK. A new image, a new processing goal. By design of my scope (combination of a mirror and lenses and lots of aperture), bright stars tend to be quite big. I spent a lot of time keeping them small. The method I chose was to partially stretch the image. From this image the stars were removed (Starnet in PI) and the starless image was then stretched and processed further. This sounds straightforward, but in practice I had to experiment a lot and combine a lot of versions to get a pleasing effect. A larger version of this image (with acquisition detals) here: https://www.astrobin.com/421021/

According to SkySafari it is at 03h 55m 30s +64 deg 57min 53.7sec. So at a nice location in the sky for us northerners. And here is my favorite rendition of this cosmic jellyfish by Marcel Drechsler: http://www.sternwarte-baerenstein.de/hfg1-abell6-en.html Have fun! (but you also needto capture OIII to do it justice...)

Hi Anthony, You might want to ask this also on the APT forum, but I see a few ways you could accomplish this in APT: 1a) Create a mosaic using the interplay of Cartes du Ciel and APT: http://aptforum.com/phpbb/viewtopic.php?f=20&t=2688 (semi automatic) 1b) Alternatively use the Mosaic feature in the framing aid of NINA. Use the sequence generator button and retype the coordinates of each sequence as custom objects in APT. (Manual....I do not use NINA because it lacks a few things that I am accustomed to in APT, but I have played with it). 2a) Make a plan for each custom object (Say Veilpane1, Veilpane2, etc). Do a GOTO++ for each pane (custom object) and start the accompanying plan. 2b) If you want to be asleep all the time, you can automate 2a by using a script. https://ideiki.com/astro/usersguide/scripts_and_commands.htm?ms=AAA%3D&q=U0NSSVBU&st=MQ%3D%3D&sct=MA%3D%3D&mw=MjQw This would be something like: Make a new plan in the plan editor. Let's call it VeilMosaic 4 pane In the first line, insert a script (button in the right bottom corner) like this to goto the centre of your first pane: #GoTo++ 10/Auto/RA1 DEC1 (the 10 defines a 10s exposure used in plate solving and RA1 DEC1 is the centre of the first pane according to the custom object that you made in 1a) - Define the set of exposures for this pane in the usual way - Insert the next script script: #GoTo++ 10/Auto/RA2 DEC2 - Define the exposure sequence for this pane - and so on. Save the plan and start it. Now, you asked for easy(ish). That depends on your geekness level I suppose 😉 The more complex you make it, the more testing it takes. I would go for 1a and 2a or test 2b thoroughly during moonlit nights. Regards, Anne

Hi Alexx, If you really are desperate for something off the beaten track, try this one: Heckathorn-Fesen-Gull1. It will keep you occupied for a while, but when done, you have an image of a really cool subject..and you get bonus points for remembering the name 😉 Anne

Hello Alan For mobile use, I have been very happy with a Polemaster. Works as advertised. For my yearly polar alignment in my observatory, I have been very happy with the following in Phd: 1) A classic drift alignment for Az only, Does not have to be perfect, although I tend to wait more than 3 minutes when I am getting closer. 2) After that is done (again, does not have to be perfect), a Phd polar drift alignment. At first it wanders around a lot, but it does settle down. Now only change your Alt! Get the marker at about 2/3 where it tells you that you should be. You should be a lot nearer, which makes things easier. Now let it run again and adjust both AZ and Alt to get really near to the circle. Let it run again and finish with a perfect hit in the circle. It took a little time (as it was the first time doing so), but it got me real close. No dec corrections needed in exposures shorter than 10 minutes. Hope this helps. Anne

Last March, I spent a week at Olly Penrice's place in Southern France to immerse myself in dark skies. And dark they were. Opting to spend rather more hours per target than do snapshots, only two images resulted of the week, but I am happy with the results. The first one is this: Iwamoto and the flaming star By far the most imaging time on this subject was by Olly himself. We have cooperated in imaging the comet and blending the comet with its beautiful background. The other image is the one in this post. Arp 94 (NGC 3227 and NGC 3226) It is a subject which I do not see imaged often. Maybe because the opportunity this subject offers is not well known (I found it as a relatively large Arp Galaxy in The Arp Atlas of Peculiar Galaxies by Kanipe and Webb). Maybe it is because it is a bit hard to image. It is quite close to the brigt star Sigma Leonis and as a result you have to work to avoid light streaking across the image. Both in imaging and in post processing. We fought hard to reposition the scope in many ways to eliminate the light reflections while imaging, but the only way to completely eliminate them resulted in the main object being at a far corner of the image. Not good for composition. So, we opted to allow some light streaks and do cleanup in post processing. 20 hours of mono imaging was done at Olly's place and I added 7 hours of color imaging from my back garden observatory at home. I had my first steps in PixInsight processing this image, but most of the heavy lifting in clean-up was done in Photoshop. For those who like to know more on the physics ,I have done a write up of NGC 3227 and NGC 3226 on Astrobin: Arp 94 by Annehouw on Astrobin