Search the Community
Showing results for tags 'drift alignment'.
Found 6 results
If you are using an auto-guiding scope and ccd with PHD, do you need to worry about drift alignment and/or periodic error correction of the mount?
Hey guys, following on from my last thread regarding drift alignment issues, I finally (after a year and a half of trying) managed to get what seemed to be precise polar alignment using the drift method. The goal of this is to get long(ish) unguided subs. My setup is a Skywatcher NEQ6, SW 80ED Refractor, Canon 100D DSLR and i'm using BackyardEOS to control the camera. I don't yet have a focal reducer or any form of autoguiding. Here is an image of my altitude alignment (using the D.A.R.V method), using a star at around ±10° dec from the celestial equator, as near to the east horizon as possible. (Apologies for the poor image quality - I had to use my phone camera since print screen didn't seem to want to work on the laptop). And here is my alignment for the azimuth (taken near the meridian at ~0° dec). I spent hours trying to get both as precise as possible - I think more precise alignment would have been next to impossible for me to do. Regardless, after finally feeling like i'd got good alignment, I went to take an image and I was pretty disheartened. A 30 second exposure left me with significant star trails. The longest subs I could get without trails were ~15 seconds. After nearly a year and a half of just trying to get good polar alignment, it feels like a bit of an insult, especially given that people often talk about getting 30-60 second unguided subs. But, i'm determined to eventually get there. So my question is, why is this happening? Could it be that my mount is flawed or damaged from the time I dropped it on my head? Do I just not have enough practice making the small adjustments to the mount required for unguided subs? Could balancing play into this? I've tried to balance my mount as best I can, but the dec axis is still heavily skewed towards the back/camera end of the scope and i'm unable to move the scope any further forward on the dovetail to counter this. Or could this be that i've simply hit the limit of my setup? I was always intending on buying an autoguider once I was familiar with my equipment and able to get good polar alignment, but would it be worth it? I'm a bit worried that if I can't get better alignment, an autoguider really isn't going to make much difference (and at best give me bad field rotation). Alternatively, are there any other methods of polar alignment I could use? I don't really want to use the polar scope method, and would prefer drift alignment if possible. I'm aware that pHd has a drift alignment procedure, and i'm tempted to try it if I do end up getting an auto guider. Any help or discussion is much appreciated! Cheers, Crowmium.
Hi all, Just wondering if anyone could help me out with a bit of weirdness that was happening last night as i was trying to polar align my NEQ6 mount. I'm using the drift alignment method found here with an exposure time of 125 seconds - 5 seconds where the mount is still in order to 'burn in' a starting point, 60 seconds slewing 'left' and then 60 seconds slewing 'right'. Often, the resulting image wouldn't be in straight lines, but rather lines with kinks in them - the image attached should help give a clearer image of what I mean. This happened when i was aligning both the azimuth and altitude axes. Does anyone have any idea what might cause this? Could it be mount damage or am I just not holding down the directional keys on my keypad properly? Many thanks!
Hi all, I was just wondering... I've been looking for eyepieces to do drift alignment with, and as per this video: http://www.andysshot...tAlignment.html and after trying out with my own 5mm eyepiece (without reticle), I wanted a 5mm reticle eyepiece. But searching it turns out there are practically only 12,5mm illuminated reticle eyepieces... The 5mm Orion seems to have been discontinued... Anybody have any idea why this is? Did the 5mm cost too much? As I see it a 5 mm would do nicely, because one easily sees the direction a star goes, when turning off the motor drive, and I'm guessing it would also be better for detecting the drift. More so than with a 12,5mm... Thanks for any ideas, thoughts! Gerhard.
Hi all, Just another update on my progress thus far... I had some good nights recently, with rather variable results, so wanted to share, and hope to receive some feedback on my musings as to the causes of the differences. First I went high up (1600 m) on a quite clear night, with also good seeing, and I was able to take this: Then, last week, I went less high (1000 m), good clear night, but with some more light pollution, but (IMHO) with better setup: The latter image was done doing drift alignment, AND PEC on my HEQ5 SynScan. The former only with drift alignment. I also tried the M31 on the second occasion, but it was much lower than the NGC6960 (which was close to zenith) and it has terrible traces and other anomalies: I had to dump a lot of subs... :-( So, as you might see, the stars in the second image are much better, but the light was better on the first image... I am obviously still also on a steep learning curve, so that might also have contributed... Question: how much of the quality of the stars in the second image do you think is due to the mount being better balanced pointing to zenith? If this is a significant amount, that would mean that for now I should limit myself to zenith objects, to obtain quality subs..... :-/ Second question: do you think making flats would help with the obvious lighting problems on the second image? Friday maybe I'm going out again, and will have another try at the NGC6960, or maybe its sister NGC6992... There's a full moon, though.... :-/ Thanks!! Gerhard.
Hello! Im trying to do drift alignment for astro'photography. I read the basics but im facing some doubts, because i have my setup on a balcony, which is facing SW, meaning i can clearly see, from left to right (obviously,lol), South, SouthWest, West and NorthWest. The major doubt is: is it in anyway possible to drift align in this conditions, not having a star in the East available and also not having polaris available? I would appreciate some input from you all! Thanks, Cheers Rui