prusling

Hi, sorry not to get back to you sooner re StellarMate. I've drawn a blank I'm afraid - not so much on whether the QHY183c is supported (though see later) but more in getting a reliable connection. Previously I've just played with StellarMate via VNC close to my wifi router and it's worked fine but I have all my kit in an obsy so can't easily test connectivity inside the house. SGP just works for me so there has been little incentive other than to minimising cabling. I've been able to connect the mount and the motor focuser OK but it hangs when I move onto the camera tab. If it's not too off topic maybe you could help me by describing how your network is set up and in what mode you use it. I have a main router at the front of the house as it needs to be close to our security camera, and a repeater at the back of the house which covers the garden reasonably well and allows the laptop to connect in the obsy which is c. 10m away. I've tried locating the Pi in the obsy and it connects OK via the repeater, and used RealVNC on the laptop which also connects to the repeater OK. However the Pi is very slow in this configuration. Is there a better way to work?

Hi again, I don't know whether you are aware that there some excellent tools under "Info" at FLO's website. They give the following data for your potential/current setups (you'd better check my calcs!): OrionED80/QHY183c Max Res 1.45 a-s, Pixel scale 0.83 a-s/px (so you'd be limited to 1.45 a-s by the scope aperture) and good match for OK to good seeing SW200PDS/QHY183c Max res 0.58 a-s, Pixel scale 0.5 a-s/px (so you could pretty well get the full res of the camera) but categorised as "This combination leads to slight over-sampling. Will require a good mount and careful guiding." For your current setup: OrionED80/Atik314L+ Max Res 1.45 a-s, Pixel scale 2.22 a-s/px and good match for poor to OK seeing; good seeing categorised as "This combination leads to significant under-sampling. This reduces the influence of guiding errors and improves signal to noise at the expense of finest detail. May be OK for widefield imaging but might result in softer images." which is no great issue in my experience SW200PDS/Atik314L+ Max res 0.58 a-s, Pixel scale 1.33 a-s/px and very good match for OK seeing with good and poor seeing not bad If you add a reducer to the OrionED80/Atik314L+ combo it makes the under-sampling worse though with my even worse setup I have never really found this a problem. I'll give Stellarmate a go a bit later. In the meantime, here's my latest image with the 110mm scope and the 183c for a total of c. 2 hours - I was gentle on the noise reduction to retain the dust clouds.

I have Stellarmate but haven't used it in anger yet (I use SGP). I'll try connecting it up tomorrow. and report back. A step up? The Atik is a very fine low noise camera that I find works very well with narrowband (I rarely use LRGB). The 183c is a quality OSC with great cooling and small pixels though I find it a little hit or miss - it seems to need a darker sky background and that's not easy to achieve from an urban setting. When it's good it's very good but it can also be disappointing. As noted the file sizes are much bigger and with short subs you can end up with a lot of space used / transfer times and longer preprocessing time. To me they are complementary and both are keepers! Peter

I have both the Atik 314L+ mono and the QHY183c colour and I would say that they serve different purposes. I have been using the Atik on an 80mm f6 frac reduced to 390mm. According to the prevailing wisdom this is highly undersampled but it works very well for me for wide DSO targets. The 183c also works well with this scope though I understand that the aperture gives a low Dawes limit so resolution is being lost. I also found that the field of view is too wide for the smaller spring/summer targets so I recently bought a 110mm f5. 95 frac with only a flattener at 655mm and have been using the 183c with it to good effect. I am a lazy imager and try and avoid calibration frames - the Atik works very well using a single bias master as a dark at any temperature. I run the 183c at - 20 all year round and have a set of matching darks at varying exposure durations which fully remove all amp glow. I use an OAG on the 80mm mainly to free up the upper dovetail for power and data distribution. It works pretty well considering the base of the prism was chipped when I bought it! Happy to answer any questions you have.

Hi Karen, there's a very sociable club called Fordingbridge Astronomers who (in more normal times) meet near Ringwood on the 3rd Tuesday each month. You'd be very welcome to join us when we resume (or on Zoom in the meantime) - http://fordingbridgeastro.org.uk/index.php

A while ago on my 550d I used a 1.25" Ha filter inside a T adaptor by utilising a sawn-off T2 nosepiece which was fully threaded for filters! It showed vignetting as you would expect but a good proportion of the image was OK.

Another option which probably works on a similar basis to the Concenter is to use a camera with lens to image the secondary, in conjunction with free software showing overlaid concentric circles to help to circularise and align it. This does require a camera so may not help the OP (e.g. a webcam with original lens not removed and a 1.25" fitting, or an add-on lens to an astro cam such as a wide angle meteor lens). See the excellent YouTube video by AstronomyShed entitled "Advanced Newtonian Collimation".

Correction - it's PHD not EQMOD that supports drift alignment

Hi again, There is an alternative means of polar alignment if you cannot see Polaris - drift aligning - which is supported in EQMOD and other imaging software such as APT (also recommended and great value). In this method instead of the celestial north pole you point to a star on the celestial equator (0 Dec) first to the South and then to the West and create a trace in one direction then the other - if PA is out this will show as a "V" shape and adjustments can be made until the angle of the "V" disappears. There is a good article on this at https://www.cloudynights.com/articles/cat/articles/darv-drift-alignment-by-robert-vice-r2760 The guiding software needs to control the mount to make small adjustments to keep the guide star in position and there are two main ways - 'pulse guiding' connects from the computer running the guiding software (e.g. PHD2) directly to the mount's serial port, whereas ST4 guiding uses a cable from a guide port on the camera to a guide port on the mount and the software sends its corrections via the camera to the mount. Whilst the latter sounds neater I believe that the level of control achieved may not be as precise as that from pulse guiding. There is a possible third method where the computer connects to the hand control instead of connecting directly to the mount but this can be problematic. Hope this helps

Hi, you have a great mount for astrophotography! The only use of the 'circle dials' you need is to help you set your Home position to start from (usually scope pointing North with weights down). To do this you first take the scope and weights off and with the RA clutch loosened point the mount roughly horizontally, place a spirit level on the extended counterweight bar, rotate in RA until level and lock the clutch. You also use the spirit level across the saddle in a similar way until Dec is also level. You can then set the dials to any known positions (e.g. multiple of 90 degrees) and turn the RA and Dec as close to 90 degrees as you can get until the scope would be pointing North with the weights down. You can now use a Sharpie to mark a thin line across both planes so that you can more quickly reposition them in future. The next task is to polar align so the mount (and scope) is pointing exactly to the celestial north. As you will be guiding I recommend using SharpCap in conjunction with the guide camera. There is a function for polar alignment (I think it is only on the paid version but its excellent value anyway) which takes images of what it can see through the guidescope, matches them to a database of star positions (plate solves) and tells you how to adjust the altitude and azimuth bolts on the mount itself until it can tell that the star positions are those that match celestial north. As you will be guiding this doesn't have to be absolutely perfect but the closer the better. You also will have needed to balance the scope and weights so there is only a little stress on the motors. For using PHD2 you'll need EQMOD (free) to control the mount along with a suitable USB adaptor cable. This may all sound a bit daunting, and I held off guiding for a long time before taking the plunge, but once you get the hang of it, it becomes second nature. Happy imaging!

There is a third party pre-processing front-end for siril called sirilic which I have used to good effect: https://astroslacholet.wordpress.com/2019/05/12/utilitaire-conv2siril/ The page may need translating from French but the tool is multi-language. I wrote a short guide to its usage which is linked to on that page.

@johninderby Many thanks for this approach. @AdeKing pointed me towards an earlier post of yours describing it, and I recently completed the flocking of a new-to-me SkyLiner 200p. I'm delighted by the result - it was so much easier to stick the flocking to the backing material with it lying flat on a table. For anyone interested in adopting this approach for a similar scope in the UK, I used 0.5mm x 1050mm x 750mm Black Polypropylene Sheet from kitronik.co.uk which had the right 'foldability' whilst retaining its shape, along with the recommended d-c-fix® 348-0005 Sticky Back Self Adhesive VinylFilm Black Velour 2 x 45cm x 1m from goodswholesale.co.uk. For the 1200mm FL Skyliner the 1m length of the velour finished just short of the 1050mm length of polypropylene (PP) and I trimmed all the excess off - if I did this again I'd leave maybe 20mm uncovered which would then extend down the sides of primary and better match the tube length. The PP width of 750mm is a close match to the inner circumference with a slight overlap and there is just one join where the 2 x 450mm rolls of flocking material abut, with the remainder trimmed off for other purposes. I didn't make holes for the Dob side bearings and instead refitted them using shorter A2 Stainless Steel Socket Countersunk Screw Allen Key Bolts M6 6mm x 30mm from Amazon (I have loads of these left if anyone needs some) which hardly protrude or deform the inner tube. I cut out a rectangle for the focuser and gaps for the spider vane fittings and poked through manually with a drill bit to refit the finderbase (not shown in the photo). Having done this I didn't even need to stick together the two sides of the PP to form the tube as the material holds it shape against the OTA. Thanks again for this approach.

I also have this Powerstrip and it's doing great service mounted on an extended upper dovetail along with a USB hub thus limiting the number of cables between the scope and the mount. It's good value but took a little while to arrive from HK.

Hi, I bought one of these: https://www.amazon.co.uk/dp/B06XSCCLCD/ which I power from a 12v distribution block. It seems to do the job though I haven't used it much in anger. This particular brand is no longer available, but there seem to be others that are similar.

I found the StarTech USB2 became unreliable below 0 degrees (as per spec). Switched to Orico USB3 and no problems so far though it hasn't been as cold.

Just received a set of the new Baader aluminium fine adjustment T2 spacers/shims to replace the delrin shims I've managed to lose (though they were a nightmare to get on/off anyway...). The metal ones come individually in 0.3mm, 0.5mm and 1mm sizes, each in their own fetching colour, or as a set of three, and there are M48 variants as well. They are slightly oversized and do not need to be threaded on, are more resistant to compression and seizing up, and promise to make the frustrating job of fine-adjusting back spacing much easier!

Just search for "skywatcher crayford focuser adjustment" and you can view the pdf

Hi, that was wasted as a guide scope! I had one for a few years and only sold it to upgrade to a triplet. The optics are excellent; don't worry if they are slightly dusty - it's inevitable and doesn't significantly impair the view/image. The main weakest point is the stock focuser and how it is fitted (three screws); it is serviceable but benefits from an update - either to the SW upgrade or third party. I found that the stock focuser needed adjustment to optimise traction and hold - there's an excellent guide on the web and will see if I can track it down again. You just need to check that it runs smoothly in/out. I also found that the 3 screw fitting left it slightly out of collimation - this can readily be check/adjusted by creating a suitably-sized card circle using a set of compasses which leaves a hole in the centre; I took the dewshield off and put the circle just inside ahead of the lenses. If you put a (collimated) laser collimator in the focuser it should should shine straight through the hole in the card - if not slacken off the fitting screws and adjust the fitting before re-tightening them. These are minor issues for what is an excellent scope - go for it, you'll enjoy it! P.S. You'll need a reducer/flattener for imaging but that's true of all such scopes.

Hi Matt, welcome to the group. Others will contribute suggestions I'm sure, but here go mine: As you say, Durlston and Badbury Rings are favourite spots along with Hyde Common near Fordingbridge and Steeple ridge near Wareham. There are also various sites with interesting foreground features - St Aldhelms Head, Durdle Door, Knowlton Church, etc. Cranborne Chase AONB is applying for International Dark Sky status and there are various sites within that area. One option is to join one or more astro clubs who hold sessions at these venues - Wessex Astronomical Society meets in Wimborne on the first Tuesday each month and has an observatory at Durlston with regular public/member sessions, and Fordingbridge Astronomers at St Ives near Ringwood on the 3rd Tuesday also holds sessions at Hyde Common and other locations. We also have informal get togethers with members of this SGL club. What are your preferences - visual and/or imaging? DSO/planetary/solar/lunar/widefield? Hope to see you at one of the meet ups.

StarTools is one tool that can interpolate green from Ha (as red) and Oiii (as blue) giving images where the Ha comes out a rich golden colour. I sometimes process using the Ha as Luminance as well but that doesn't seem to make much difference. I also have an Sii filter but struggle to capture enough with it to avoid Hubble SHO coming out over-green.

Article on 1:1 pixel resolution by Jerry Lodriguss

I have a 550d and it has been superb. It and only one other (60d) have a special movie crop mode where the middle of the sensor is used to record 640x480 1:1 video for e.g. planets. With all Canon cameras they can develop a degree of banding but this can be removed using Fitswork4 or other tools.

Fantastic info, many thanks. I'll digest it and have a go!

Hi, I saw this old topic referenced in a current thread and wanted to ask how you conduct a Roddier test. I also have a TS 80/480 - of 2011 vintage - and I seem to get a spread of colours within stars - with red more prominent in one segment. I'd like to determine whether it's the scope or another part of the optical train.

I now also read that binning the guide camera 2x2 can help in such circumstances - is this recommended? Thanks for any guidance.