Back in January ('99) I found myself struggling to get even poor astrophotos out of my 8" LX50. For more information on the problems encountered, Click Here. At that time I decided to upgrade my mount to something more suitable for astrophotography. At first I thought about the Losmandy GM-8 to mount my 8" SCT on. Losmandy has an excellent reputation for making very accurate mounts. After some discussion (with others on the APML list serve) I found that the GM-8 might (I say might because there doesn't seem to be any real consensus on this opinion) be a little undersized for my 8" SCT. I looked at the GM-11, which is an overwhelming favorite among astrophotographers. Someone then mentioned (Wil Milan I think) that I might take a look at the Mountain Instruments MI-250 also.
After visiting the Mountain Instruments web page and comparing the GM-11 to the MI-250 I decided to go with the MI-250. The MI-250 is a bigger mount and can carry a bigger payload. After calling Larry Myers and asking some questions about options I took a weekend to make up my mind. Larry Myers was very helpful and didn't try to push the mount on me. He answered my questions, told me to call back if I had any more, and then we ended our conversation. I really liked the larger 7.5" Byers RA drive and the fact that the MI-250 uses a tangent arm DEC assembly (NO backlash). I called Larry on the following Monday to order my drive (I also went with the high resolution 8000 step encoders, digital setting circles, and the MI-8P Pier).
After a month or so, Russ Dickman noticed a posting I made on the APML listserve that mentioned that I was waiting for my MI-250. Russ fired off an e-mail to let me know that he had been using the MI-250 for a while and was very satisfied with it. He graciously offered to help me with any questions that I may have with my new mount (if you want to see some great astrophotos, you should visit his web page. Ancient Light by Russ Dickman). After a couple of e-mail's back and forth we got on the topic of his AP130EDT. I knew I wanted to go to a good refractor someday so I was interested in where he got his and how much they cost. To my surprise I found out that Russ had an extra AP130EDT that he was going to sell soon. I knew there was a 2 year wait for these scopes and didn't want to pass this opportunity up. I bought the AP130EDT and a 80mm Celestron guide scope from him.
Both should arrive in the next week and a half. I plan on detailing my experiences on both setting up the equipment and my first couple of nights operating the equipment.
I received my MI-250 Mount and AP130EDT and have begun the learning curve of this new mount. Both fared the UPS trip without any problems.
Unfortunately, I had problems with my Parallax rings. I ordered my rings 6 weeks prior to the arrival of the rest of the equipment. When I initially called Parallax to order the rings they let me know that they were in the middle of a move and it would be a couple of weeks before they could get to the rings. This was really no problem because I didn't need them for 6 weeks. Well, weeks went by and no rings. To make a long story short, I got the rings a couple of days after the rest of my equipment and was a little disappointed in their condition. The were only drilled and tapped on one side (I requested that they be drilled and tapped on both sides for a guide scope). The location of one of the holes was 1/32" off center. And to top it all off, they put the rings in the mail before the paint was dry so I have a nice "Bubble Wrap" texture on the rings.
That said, I still think the rings are nicely built. They are very solid and make getting my OTA on and off the mount very easy.
|PLEASE SEE UPDATE BELOW (DATED4/14/99) for more info on my Parallax experience.|
The Mountain Instruments MI-250 is great! The mount and pier are solid and sturdy. I was out in wind gusts of +10 Mph last night and the stars didn't move at all (because of the wind anyway ;-). This is a great departure from what I was used to with my Meade 8" LX50. I noticed the tracking was not keeping the star in the FOV very long which made me worry a bit! It got cold very fast with the wind so I decided to wrap it up for the night. Once I got in, I realized that I had loosened up the clutch for balancing the mount then didn't snug it up again. Getting the thing polar aligned is going to take some getting used to. Without setting circles or polar scope it took me a while to get the thing anywhere close to aligned. I think I can alter my Tuthill Precision Polar Alignment Scope to work with the MI-250. I'll add a section with that info as I get to that project.
I am really wanting to get the AP130EDT mounted up and taking pictures but I need to get my Parallax issues resolved. I'll add more then.
I had a small problem with the MI-250 electronics. Larry Myers took very great concern with my problem and provided me with excellent customer service. He pursued, diagnosed, and corrected the problem promptly and actually offered me a free polar alignment scope for having to deal with the problem (I don't think Meade would have made an offer like that ;-) With that behind me, and my Parallax rings ready to go, I have had a few chances to trial run the mount and new OTA. All I can say is WOW! The mount tracks superbly! I will try to put some numbers to the PE but for now I think I am getting around +/- 6 Arc seconds of PE (with PEC trained). The AP130EDT has amazed me also. The pinpoint stars and contrast are unreal. Hopefully soon I will have some pictures to show and I will see the quality of astrophotos that I always wanted to take.
I got home today to find an interesting e-mail from Joe Nastasi of Parallax Instruments. He had gotten wind of my dissatisfaction with my rings. He apologized about the bubble wrap texture on the rings and offered to refinish them free of charge if I wanted to send them back. They had just tried a new painting procedure and didn't know that the rings needed longer to cure. He also mentioned that the holes may not be as far off as I thought and that I should check the holes in the Losmandy DC-11 Plate to make sure they were a true 3 1/2 inches apart. To my surprise, when I checked, they were not! They were about 1/32nd of an inch too close. If anyone has ever tried these plates, you know that the tolerance for getting the fasteners threaded is not very large. In my case the 1/32nd of an inch made it impossible to get the fasteners threaded. The problem of one of the holes being drilled slightly off center still holds but this didn't prevent me from mounting the DC-11 Plate squarely with the rings because one side of the DC-11 plate has elongated holes to accommodate this.
First off, I would like to apologize to Joe and Parallax Instruments for any incorrect information that I may have presented earlier. I think it says a lot that Joe heard about my problems and contacted me to make things right. It's that type of customer service that makes me return to a vendor over and over. I would highly recommend Parallax Instruments to anyone who is looking for high quality rings to mount there OTA with. I say this because I think my situation was a result of Parallax being in the middle of a big move and was a very isolated incident.
This really isn't an MI250/AP130EDT experience but thought it may prove useful to someone doing astrophotography.
I just recently spent 7 hours under the stars getting some shots from my back yard. It was a beautiful night with no moon or clouds. It had been about 3 months since I last got out mostly due to bad weather. I setup to shoot M8 and had a bit of a hard time getting my ST-4 to guide. Once I found a suitable (bright enough) guide star, everything worked wonderfully. I had to cut the exposure a bit short (30 min) because it was getting to low on the horizon (low enough for the street light to be a problem). I then decided to try out my Piggy-Back mount that I had just recently completed. I took about 5 shots of the North American Nebula (5-15 minute exposures at f4). I then turned my attention to the Andromeda Galaxy and took about 3 more shots. It was getting late (3 AM) so I decided to wrap it up for the night.
When I got the film developed the next day, it came back totally blank! The film was very dark brown and the edge markings were gone. I was using my first-ever hypered batch of Kodak PJM-2 film. So right away I though that I had screwed up the film. With some help from others on the APML listserve, it was thought that possibly the guy who develops my film had exposed it to light somehow. This deduction was made because the edge marking was gone and even if I had over-hypered my film, they would still be visible (faintly). Well I decided to do one more check on my hypering chamber to I bought an external thermometer to check that the chamber was holding temperature correctly. To my surprise, the 50C temperature sensor was not functioning properly, letting the chamber heat up to around 75C! It torched my film. So much so that it destroyed the films ability to be sensitive to light.
The one thing I learned from this is that when you are hypering film, you must be sure of the conditions of the chamber, and that you must standardize your procedure. This may entail getting a few rolls of film developed with out any images on them (costing some money) but I would have wasted $50 bucks on film to have that one night back!
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