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Steve_Field

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About Steve_Field

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    Nebula

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    Fayetteville AR
  1. Had not thought about filling the legs with sand... thats a good idea. To stabilize the mount, aside from tightening the bolts on the legs and all the other recommendations I've read about this mount, I set it up with the legs completely retracted, got the mount level amd pushed the bottoms of the legs into the ground a bit, then I piled 12 lbs of bean bag weights that I normally use for scuba diving on the eye piece tray. I'm going hit the hardware store tomorrow and build something that will let me hang the weights under tray to move the tripod's CG even lower... but I have to say the soft bean bag weights work great for this
  2. No doubt Ken, lately it seems like the clear nights are few and far between and with Christmas parties and family stuff I've found that I've had to do a lot more planning to get set up.... Wife made me play dominoes with the kids on Wednesday night and completely blew up the entire evening for me! Now it looks like it'll be overcast down here until next week some time grrrr.... so much I'm dying to try out next time.... prbably need a checklist now! So I've not touched the focuser on my scope since I took the M42 photos... I suppose I could take some flat frames with it. The only reason I hadn't was that I thought the telescope needed to be at the same temperature as it was when I was imaging.
  3. I figured more frames to stack was the ticket. I just started fooling with DSS which beats trying to stack in PS. Curious about dark, flat and bias frames will those help as well? You know the Pentax was also a hand-me-down that was just sitting in a closet and it may very well have a bulb setting but it's probably buried in one of the many obscure menus on this camera. It's OK for a free camera but i'm going broke keeping it in batteries ... i only get about 15 to 20 frames at 30 seconds before I get a battery depleted message and the camera shuts down. I was going to get an AC adapter for it before the offer of the Nikon came along.
  4. Also, the old Pentax K100D only allows for 30 second exposures and really lacks in features. I've got a wealthy friend who has a camera addiction problem that just gave me his old Nikon D80 ... still an older camera and not a Canon but I think it'll work a bit better than my 10 year old Pentax. I'm really curious how you modified your focuser... any details you can give me?
  5. Hey Nigel, Thanks! Actually this was taken without a barlow lens (I moved the primary so that I could remove the barlow fro the optics train). I have a Celestron Nexstar 130 SLT which tracks pretty well when I take my time and get it properly aligned. I love the telescope for it's ease of set up and precise go to puts the faint fuzzies dead center of a 9mm EP but to be honest the focuser leaves a lot to be desired... it's incredibly cheaply made and requires a very heavy touch making minute adjustments really difficult. I added an Orion Accufocus which helps but I've been seriously considering dropping some cash on an after market focuser
  6. OK so I saw this thread recently and it inspired me to start trying to image DSOs with my old Pentax K100D and Celestron Nexstar 130 SLT. I've gotten a few images of M42 amnd M31 but the stacked images have not been all that impressive. I had to use a barlow lens to get my dslr into focus and I kept thinking that perhaps with the focuser racked in so far and with a barlow lens in the optics train that i was not getting as much light to the senor as I could so i set about to try and remove the Barlow lens from the equation. I built some extensions for the collimation screws and locks screw by fabricating bolt couplers out of 3/8 IN rolled steel and tapping them with 5mm x .8mm threads... that size not being readily available around me. The whole modification cost be about $15 US and moves the primary mirror about 250mm closer to the secondary which lets me focus my DSLR without needing a barlow lens AND I still have enough backward travel in the focuser to use an EP if I want... the mod is easily removed or added and could be done in the field if necessary which was my primary design consideration. I don't know if anyone is interested in the details of this mod but let me know and I'll post a detailed thread with pictures in the DIY section. I did a quick test from my driveway on Wednesday night using a stack of 9 images with a 30 second exposure (no darks, flats or bias frames due to having limited time). I keep reading that 20 seconds is the max exposure you should be able to take on an ALT AZ mount but I got 9 good frames out of the 11 at 30 seconds so I'm convinced that 30 seconds is OK and I could maybe push that a little more (and believe me I'll be figuring out where the upper limit is over the next few months). Anyway, this is my 3rd DSO imaging attempt and while it's not great, it did make my jaw drop and I'm pretty happy with it. Next go round I'll see what I can get with the same camera settings and maybe 50 or 60 frames plus darks, flats and bias frames to see if I can get a better image. I also want to have a go at M31 at some point over the next few weeks. Anyway, I thought I was limited to lunar and planetary imaging with my set up but this thread has shown me that quite a lot is possible with an ALT AZ mount...
  7. Thanks guys! Yep, now that I've got the scope configured and the camera settings figured out I will definitely use a bunch more exposures next time! Forecast is for cloudy nights for the next 15 days but a few of them are to be partly cloudy so I may be able to find a sucker hole one night to shoot something through.
  8. I finally bit the bullet and came up with an easily removed modification to my Celestron 130 SLT to move the primary mirror about 2.5 CM closer to the secondary so that I can mount my DSLR to the focuser and have enough inward travel to be able to focus the camera. Previously I had to use a 2x barlow lens to be able to focus and I just wasn't getting the kind of results I was wanting. Getting the Barlow lens out of the way makes a HUGE difference!!! This is a stack of 9 30 second exposures at ISO 1600 (I tried ISO 3200 but what I was getting back was too noisy) stacked using DSS. I did quite a bit of post processing to stretch the histogram, bring out more colors etc. (I still have a long way to go learning PS). Totally shocked that I was able to get away with 30 second exposures using an ALT AZ mount too... I had 11 images but 2 of them had a significant enough star trailing that right or wrong I didn't use them Anyway here is the result! I know it's very far from the kind of work I see here but I don't think it's too shabby for my 3 attempt at AP! What do you think!!
  9. Here's my first DSO M42 Orion Nebula http://astrob.in/276679/0/ This was a stack of 6 30sec exposures stacked with DSS and then processed in Photoshop to stretch the histogram... still need to work at it as you can see. Going to retry tonight using the Bahtinov Focus mask I built (for better focus) and a stack of at least 40 shorter exposures along with a bunch of dark and bias frames....we'll see what happens
  10. Well, just to update you guys... I'm not sure which of the issues describes was the root cause (maybe all) but after loosening the clips so that the primary turns freely, doing an accurate collimation and cleaning things up I now have a working telescope again! Last night was clear and cold but I was able to achieve very sharp focus o the moon, mars with and without a 2X barlow (I will say it did take a bit of tweaking to find the focal point with a Barlow but I eventually got there) as well as m42 so I think I'm good to go now! Thanks for everything! Cheers! Steve
  11. Thanks CJ....So if the mirror clips are too tight is it possible for the mirror to become distorted? Is that what is meant by a pinched mirror? For what it's worth, I loosened the mirror clips, re-centered my spider and re-centered the secondary mirror and adjusted the tilt and finally lined up the primary and I'm sure of the collimation now. It'll be cloudy every night for the next week or so but I'll let you know how the star check goes as soon as I have a clear night. Thanks for all the help guys!
  12. Peter, I did take the primary mirror out to clean and not knowing any better I did dog down those clips pretty tight... i know for a fact it won't rotate so I'll go back and loosen those up. That is a piece of information I did not have in my possession so thanks for that! Noah & Barkis, The Orion electronic focuser is just a step motor that attaches to the original focuser by removing one the knobs and coupling the motor's shaft to the focuser shaft with a flexible sleeve... so I'm using the original focuser. This thing just allows me to rack the focuser in and out without touching the telescope thereby eliminating some of the bounce. Last night was cloudy so I was tinkering again and did notice that with a draw tube inserted and the focuser racked all the way in so that the circle of the secondary mirror's edges were just visible that the secondary was not centered but slightly low (perhaps 2 or 3 mm)... I can bring it to the center by adjusting the spider vanes but that means the spider is no longer perfectly centered which leads me to believe that perhaps the focuser isn't squared tot he mirror and I wonder if the OTA is a tad out of true as a result of the fall (although I don't see any obvious wrinkles in the OTA and the fall was less than a meter... my 2 feet t most but it fall on asphalt so it got a good jar). I'm going to see if I can use some paper shims to get is squared today. Maybe it's not a big enough issue to fuss with but a least I can eliminate it. My biggest concern is the star test... I've got plenty of travel both ways on the focuser yet I'm not seeing concentric circles but rather a fuzzy round blob which leads me to believe that the root cause is on the optics as Peter suggests. I guess that some of this could be a matter of my own expectations, Jupiter, Mars and Venus are fairly low on the horizon now so I am looking through a lot of atmosphere and of course while the telescope says Celestron on it it is nowhere close to the same level of quality as the old orange C8 or other new more high end telescopes. In the end you always get what you pay for I suppose but I'm not giving up on this as I'm sure with a bit more TLC I can get some pretty acceptable views. As a backup plan it turns out that Explore Scientific (http://explorescientificusa.com/) is based not a few miles from me and has a showroom and manufacturing facility here for their telescopes and eyepieces. I met one of the guys there yesterday and he has generously offered to take a look at it next week if I can't resolve the issue. BTW, I was utterly astounded at the level of quality of the Explore and Bresser Telescopes they manufacture and sell ... I was especially impressed with the f/4.9 Newt/Mak Comet Chaser and the 8" Newtonian they had on the showroom floor. What a disaster this has been! On the plus side I really have a much deeper understanding of my kit and feel like i'm well on my way to being a competent technician. Heck, I'm even beginning to think I may be able to build a telescope one day even (there's a 10 inch mirror in the old man's basement with my name on it if I want it) Thanks for the input guys, it's really appreciated! I'll let you know how it goes. It maybe fairly clear early in the evening tonight so I may be able to do another star check if I can get after it early enough. Cheers! Steve
  13. Hello everyone, I've been lurking around SGL for a few weeks and I really need some advice. I'll apologize upfront as this may be a rather long post but I think context may be important here. So to begin, I'm sort of new to astronomy. I say sort of because while I was brought up around telescopes (my father has been using the same orange Celestron 8" SCT since he bought it in 1978) and know my way around the night sky with a pair of binos, I recently bought my first telescope (A Celestron Nextstar 130 SLT). I made the purchase decision based on the fact that the old orange Celestron is still a very fine instrument in spite of it's years and because I figured being as light weight and easy to set up as it is that I'd get it out and use it more often. I'm generally happy with the purchase and have done quite a bit of view but I'm having a bit of trouble that I hope you all can help me work through... here begins my tale of woe... When the telescope arrived I set it up in the driveway, leveled it and familiarized myself with the alignment procedures and actually did a bit of decent viewing it being a clear night and was utterly re-hooked on astronomy. The second night, my wife and I drove out of the city and LP to do some viewing. When I set the scope up the dove tail on the OTA was slightly crooked in slot on the mount and consequently not really snugged down. After a bit of slewing, the OTA slide right out of the mount and struck the ground tail first...self inflicted wound #1. Luckily nothing broke but as you can imagine it was horribly out of collimation. I got a collimation tool from celestron that's basically a draw tube/Cheshire tube combination and set about the reading everything I could on collimating a Newtonian telescope. I did finally get it back collimating (I think) after several hours of fiddling (the secondary mirror gave me the most trouble and in hindsight it was probably not wise of me to have removed the entire spider and vanes from the OTA to see how it worked) Self inflicted wound #2. I was largely unimpressed with focuser on this telescope as well. It took quite a bit of torque to actually turn the knobs and with a 6mm eyepiece the bouncing made achieving focus pretty frustrating. Being the mechanical sort I took the assembly apart and discovered it was packed with some sort of "lubricant" that reminded me more of cosmoline than grease so I got a little bit of solvent and a toothbrush and proceeded to clean all of it out. Unfortunately I didn't think to remove the entire focuser housing from the OTA and spattered this mixture of solvent and sticky grease on the secondary and primary mirrors... self inflicted wound #3. I ended up taking the entire telescope apart including the primary mirror and after several hours of soaking and in warm distilled water and a bit of Dawn liquid detergent (and 90% isopropyl alcohol on a sterile cotton ball for the more stubborn blobs of gunk) I managed to get both mirrors clean without scratching them and miraculously my cleaning was gentle enough that I didn't loose the center doughnut on the primary. I then re-assembled the telescope using a bit of white lithium grease to lubricate the rack and pinion focuser and collimated it again. I suppose the good news is that I'm completely comfortable with the working of my telescope and have a pretty good handle on how it works. I also installed an electronic focuser thinking it would help me achieve finer focus and do away with some of the telescope bounce. The problem I have now is that I can't seem to achieve a really crisp focus either on the moon or on planets. I'm getting OK focus on the moon, Mars is pretty fuzzy and so is Jupiter (on the few occasions I got up at 3am to view it). The problem seems to be exacerbated when I use a 2x Barlow lens (with a 9mm, 15mm or 25mm EP... I have a 6mm but given a 650mm focal length I wouldn't expect much at 216X magnification). In fact so much so that I've pretty much given up on the barlow altogether. What is happening is that I'll rack the focuser all the way in and then slowly back it out and the image will begin to come into focus get almost there and then starts to defocus again. This is using an Orion Electronic focuser on it slowest setting. Last night for instance I was observing M42 and after peering into 25mm EP for a while and observing with my eye slightly offset I got a really good view and switched to a 15mm EP and was rewarded with a better view and 4 stars in the trapezium but I never could get the stars to fully focus into sharp points of light. I also noticed this when I was verifying my collimation by doing a star check using Polaris ... I get a perfectly round blob (no concentric circles though) and I can't get the star to resolve into a sharp point of light. Polaris being a bit dim I tried the same thing on Vega and Betelgeuse with the same result. Again as I run the focuser out I almost get to focus and then it goes past focus. Even the moon using a 15mm EP (no Barlow) was not as crisp and I think it should be. So, what do you think? Is this a poor job of collimating on my part? Is it the eye pieces? Have I given you all enough detail to make some educated guesses? BTW, the 9mm and 25mm EPs came with the scope and the Barlow, 6mm and 15mm EPs came with an Eyepiece kit from Celestron. I'm not sure what kind of EPs they are as they only say "Celestron" but from reading I think they may be Kellners. Cheers! Steve
  14. Hi Everyone, I'm new to the forum and indeed to armature astronomy and wanted to introduce myself to everyone. As a kid my dad always had his telescope out and seeing the old orange Celestron C8 that he broke out to show my young nieces the recent super moon sparked a renewed interest. I recently bought a Celestron Nextstar 130SLT as an first telescope and have been out with it nearly every clear night happily freezing my butt off... especially the couple of times I've dragged myself out of bed at 4am to view Jupiter). Anyway, I'm grateful for this huge wealth of knowledge I can tap into and look forward to the time when I can contribute what I've learned from you all to others. Cheers! Steve
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