Legion Of Andromeda

Project completed!. I tested it last night and got perfectly rounds stars at 3 minutes duration, with 62 seconds per revolution. I managed to get the red dot finder parallel to the hinge axis.... I will post a full run down from first principles to fine tuning at a later date.

well, my project is coming along nicely 2 boards hinged with high tolerance hinges, M5 threaded rod bent to a smooth curve and passing through a hole without a hitch

I'm just about to start building a barn door tracker. My maths is good, my craft and engineering skills are very good but the idea of coding an Arduino brings me out in a cold sweat. I am sold on the concept of a stepper motor but need to control it as simply as possible with pre-assembled components..i really don't want to [removed word] about with breadboards, PCBs and soldering. so i am considering purchasing the following items to save a lot of time and stress. MOTOR; https://www.amazon.co.uk/XCSOURCE-4-Wire-Stepper-Printer-TE225/dp/B011NRMXYO/ref=sr_1_7?crid=277K22PDOS9AJ&dchild=1&keywords=stepper+motor&qid=1590313684&sprefix=stepper+%2Caps%2C139&sr=8-7 POWER SOURCE...maybe a battery pack? not sure yet.. i'm out in the field so it needs to be portable. any suggestions appreciated. DRIVER ; https://www.amazon.co.uk/TopDirect-Upgraded-TB6600-Controller-Segments/dp/B0711J1K66/ref=sr_1_12?crid=19QUZNXJ01S5M&dchild=1&keywords=stepper+motor+driver&qid=1590313835&sprefix=stepper+motor+d%2Caps%2C143&sr=8-12 CONTROLLER. https://www.amazon.co.uk/FTVOGUE-Controller-Generator-Adjustable-Regulation/dp/B07NVN2128/ref=sr_1_53?crid=188XP341U1163&dchild=1&keywords=stepper+motor+driver&qid=1590313302&sprefix=stepper+motor+driver%2Caps%2C137&sr=8-53 Once i get this all up and running, i might be tempted to get into more precise control via an Arduino, especially if the the above kit is too clunky. But the level of tracking accuracy at this stage is probably not a issue. My current thoughts on the engineering will be that the bottom block of the door has to have some mass to supress general vibrations, vibration damping motor mounts, i will be using high quality stainless steel, ball bearing door hinges. Adding an adjustable alt/ az sub-base for finer polar alignment. Any pointers on keeping things metric would be helpful, pretty much all the guidance out there is in imperial units....

Results are in! Some of this will confirm any previous replies.. Using a W.O. gt81 with a ZWO 1600 mc pro-cooled and a cheapo £50 2" optical 2x Barlow.............. I tried two extreme distances between the sensor and the centreline of the barlow lens, the first was 40mm which gave the least amount of magnification, required 163mm from the centreline of the barlow to the base of the focuser, as a reference, to get focus. The second was 120mm (by adding 2 x 40mm M42 extenders) which gave the most amount of magnification, this required 143mm from the centreline of the barlow to the base of the focuser, as a reference, to get focus. (20mm less) The ratio of 80mm / 20 mm looks noteworthy, maybe just a coincidence. This first experiment was pretty time consuming, so I didn't get into any decent data gathering... However, I did a single 2 min shot at M51 straight overhead without the barlow and again with the barlow set at 120mm... Apart from a dimmer image, it was very well zoomed-in but the optics looked pretty screwy... So i would appreciate any recommendations for good quality 2 x... Anything, unless the degradation is always an issue. More updates to follow..

Ok, i have a W.O. G.T.81 and a colour ZWO CMOS, used mostly with field flattener and sometimes with a focal reducer / flattener. I recently imaged the moon, ( i was bored / curious) but it came out very well but i was only using 20% of my sensor area, so i wondered about using a barlow... Can i use my existing optical 2" 2x Barlow in the imaging train?... and if so, where does it go ?... into the focus tube or nearer the sensor?...or half-way maybe? I'm taking the flattener out of the equation for simplicity..... Is there an optimal back-focus between the barlow and the sensor, then a simple matter of moving the two items away from the objective lens until sharp? like with a FF or FR? Ive tried today with various permutations and the images are very out-of-focus... roughly how much am i to expect to come out? 5, 10, or even 30 cm? TIA.

Hi there, it didn't take me long to tire of manual focusing via various ATP focussing tools. My most likely and affordable electronic focuser to this end would be the ZWO EAF but there doesn't appear to be anywhere to connect the bracket to the underside of the existing focusing assembly, the only two holes are the tensioner grub screw hole and the focus lock, which i assume will be redundant / free once the EAF is in place. Any suggestions from experience appreciated. BTW, for some strange reason i get a better focus simply using the APT magnifier tool than using the Batinov Aid in conjunction with my Batinov mask, which is well out.

just to confirm that you are suggesting rotating the scope in relation to the light source and not the camera in relation to the scope?

thats very kind of you thanks. i've just found an old laptop that i will use for my flats.. the t-shirt method is too variable

Many thanks but i'm not sure what you mean by this, ive not been doing AP for very long so bear with me. how do i carry out the above procedures in DSS... literally step by step please.. or post a link to useful guide / video

ok, my setup; Celestron 8"edgehd with no collimating issues, with focal reducer, unmodded Canon 6D with the correct back-focus, AVX mount, APT imaging suite, PHD guiding with minimono zwo and a half-decent laptop. Post processing is DSS using all the recommended settings..(i might have over-looked some more obsure settings?) then out to Photoshop CC 2015 following astrobackyard tutorials. Current object is Andromeda, focus is spot-on, guiding is spot-on. i recently got 200 subs - 30 seconds at 800 iso, 60 darks frames gathered at the same time plus 60 fresh bias/offset frames. However, my Flats are causing me a right load of grief. I used the white t-shirt method pointing up to a bright sunny sky (not at the sun) and got 50 of each ISO (800,1600, 3200), a set with the focal reducer and a set without, i made sure that the histogram was in the middle and adjusted the shutter speed accordingly...but what i don't understand is when it is suggested that one puts the camera into AV mode to shoot flats... AV mode is unavailable when connected to a scope via the T-Ring, so i can only use Manual mode ...at least with that camera. i might be wrong on this... I'm expecting that the flats will cancel-out the vignetting as long as the same camera/scope orientation and focus is used, so when the flats and lights are are good match that the vignetting is compensated. I don't expect it to be perfect but what i end up with are varying degrees of noticeable concentric rings, often colourful and sometimes saturated... so i'm currently trying to get away with not using my flats. so, do i need to change the way i create my flats... maybe in mono?... move the histogram to the right or left?... use more - or less?,... do they need 'calibrating' - whatever than means...?..... should i ditch DSS? I've had a good poke around the forums and found plenty on this subject but no conclusive guidance on best practice. Thank in advance for any pointers. i might upload some images later

I have significant vignetting issues with my full frame 6D. I initially assumed it was the front aperature of my Edge 8 hd. But it turns out to be the inner 36mm opening of the male 42mm projection from the rear of the 2" nosepiece. If i replace the nosepiece with a straight 2" tube held in place between the visual back and the T-Ring camera adapter this issue disappears regardless of the backfocus from 50 to 200mm. The 36mm opening is throttling the light and no amount of flat frames can compensate. Now then, my T-Ring adapter consists of a female 42mm (T2) threaded inner ring and a circa 52mm bayonet mounting ring. The inner T2 ring is kept intact by 3x grub screws, if i remove the T2 ring i find that my bayonet ring has a circa 49mm female thread! . i have found that my 48mm filter is too loose and something else i own with a 50mm thread is too big, therefore 49mm seems correct. So my plan is to find a 2" nose piece that is 49mm male at the rear end and 48mm female at the front end for my filters and circa 75mm long. I tried the official celestron adapter today only to find the same small opening at the rear end. My current setup ; My C8 SCT visual back then my Antares SCT to 2" compression collar, then the aforementioned 40mm long nosepiece and T-Ring which is currently extended by 35mm with a spare 2" cylinder held together with gaffer tape to give me the ideal total back-focus of 135mm. I also have a focal reducer, same issue, but the nosepiece only needs to be 40mm long. Does anyone know of any adapters that are male 49mm / 2" tube / 48mm female and 40mm long plus a circa 75mm long version? I'd be amazed if i'm the first person to raise this issue and that there are no simple solutions to this problem. I mean, what is the point of the Full frame sensor if one can only use a a crop-sized area? TIA.

Many thanks for all the replies and i should get a chance to deploy all the other suggestions tonight if the forecast holds up .... still early days with phd, my first try was on an EQ5 didnt need calibration (maybe it did it automatically and i missed it) and went straight into guiding for some reason, so on my second attempt i assumed the AVX would do the same. Astrophotography would be no fun if it was easy.

OK, my current setup is an 8" Edge Hd plus DSLR on a Celestron AVX mount with a ZWO 120MM coupled with a spare 9x50 finderscope for my guidescope (yes, it's not ideal but i had this working fine with my Skywatcher mount) ...The mount is optically polar-aligned to begin with, with no cone error, the optical axis is in line with the RA axis, I go though all the usual stuff on the handset and the GoTo is accurate after a 2 star alignment and a 4 star calibration giving me great Sidereal tracking for 30 second exposures, reasonable for 60 seconds and not so good beyond that. .......So I have PHD2 set up on my laptop, the correct usb to serial cable between the laptop and mount handset with the latest drivers. i have the Celestron drivers added to PHD via ASCOM, I reset all the PHD settings to default, I then connect both the guidescope and the mount with no issues then fire up the guidescope refreshing once a second, the stars are sharp. I test the mount connection with the virtual handset in PHD and the mount slews very well. ...Then I auto select a guide star and hit the guding button and NOTHING happens, the star slowly drifts off from the crosshairs with no RA and DEC lines on my graph at all. Whilst there are dozen of settings i could play with in PHD, i feel that there is something very simple and fundamental thaty i have overlooked so i would appreciate any input. Thanks in advance.