N4646W

Got my f/4 10" Mead reflector pretty much back together. Few kinks left to work out, and a lot to learn.

The focusing unit sucks. Is there anyway to modify it to get more sensitivity from it or just bite the bullet and get an aftermarket? If, aftermarket, which would you recommend at a modest price? Think fixed income, I want to get this unit up and running, and don't figure I have enough time left to save up for a top notch focus unit. I would like to stay with 2" as all the extenders and what ever all this other stuff that came with the unit is 2". Don't ask me what I have as I have no idea what these parts are used for, and google has been no help.

If the stock unit can be modified, I do have access to a machine shop.

Ron

Albuqshutterbug Loc: Albuquerque NM

Hey Ron,
One thing I did with my Celestron 6" Newt was to disassemble the focus unit and remove all of the factory grease.
It's like honey, and replaced it with Teflon grease. Take a few minutes to run a small fine file through the groves to remove any burrs.
It made a world of difference with mine. It's not what I want, but it works fairly well.
I also adjusted the tension screw that makes contact with the plastic bar on the bottom of the eyepiece holder. Mine was very loose giving me a lot of slop in the focus.
I don't know if you have tried any of this or not but it may help.
Welcome to the group and good luck.
Jim

N4646W

Thank you Jim,

So far I haven't touch the focuser yet. Didn't think of that as all the old literature on the Mead focus unit was negative. Looks like I have a project for tomorrow. I am also toying with putting larger knobs on, or seeing if there is some way to put a focusing bar on the knob as they do for lenses.

Ron

bwana Loc: Bergen, Alberta, Canada

Not too sure how you're determining focus or what you're shooting; however, if you're shooting deep sky objects, a Bahtinov mask makes it far easier to get a good focus and may make the focuser unit problem seem a minor concern...

I've never had a Meade scope but I did have an 11" Celestron SCT with a focuser knob with a lot of play. I found a used 2" focuser on an Astronomy auction site that was inexpensive and worked just fine. The biggest problem I had with the focus on the SCT was the change in focus when I slewed to other parts of the sky from where I'd obtained a good focus! I eventually sold the 11" beastie simply because it was too darn heavy to move around!!

bwa

N4646W

In among all the pieces that came with it were Nikon and Canon adapters. So I have tried to mount our Nikons to the focusing unit. Now that all the glass has been cleaned and ( hopefully) aligned, I tried to take some test shots of the mountains around here. Needless to say I would pick a time when it is either snowing, raining, or heavy clouds and fog. Cleaning the mirrors and front element made an enormous difference.

I took the advise and pulled the focus unit apart and cleaned and deburred it. What ever they used it took acetone and lacquer thinner to get it out with some vigorous brushing. It sure wasn't any type of lubricant I've ever run across. It just kept gumming up like an adhesive, and felt like an adhesive. It probably does not work as good as I would like, but it is soooooo much better. It eliminated the creep I was getting after releasing the focus knob.

Hopes are to shoot deep sky, buttttt, I have way too much to learn before I'm able to do this. Got to learn the language, what all the parts are, if I can use them and why, understanding the tracking unit. Now your throwing a mask at me. My head hurts.

Ron

SonnyE Loc: Communist California, USA

A Bahtinov mask helps a lot Ron. You may find you can do without, I'm kind of 50/50 with mine.
If I can't be happy with adjusting by eyeballing it, I can put the mask on and try it.
In learning to focus, remember that the Moon is your friend.
Then as you go further and further out, you'll need to tweak the focus back in.

You may be starting with a disadvantage though, your focuser does not appear to have a fine adjust knob.
Many/most later occuring focusers are dual speed. If you look here you can see that there is a small secondary knob. Those reduce the adjustment to a 10:1, or sometimes less, ratio. (My ED80T CF is 11:1)
In the past, often a much larger wheel was clamped over an existing knob, or replaced one of the knobs, and that made the fine adjusting easier. Tough to do with a reflector though due to the proximity of the knob to the tube and focusers frame.

Focusing was the bane of my life for a long time.
I finally built an Arduino based electronic focuser. It uses a small gear reduction motor to step adjustments at incredibly tiny fractions. Single steps are inconceivable to the naked eye.
Here is a thread where I came into this project. https://stargazerslounge.com/topic/218975-arduino-ascom-focuser-mark2/?do=findComment&comment=3130244
I've since been banned from Stargazers Lounge for being argumentative. But the link will get you to my part of the discussion.
TekkyDave is a really nice guy and helped me get over a programming error on my part where "libraries" of functions needed to be added to the Arduino's tiny brain.

But if you entertain any idea of replacing your focuser, first talk with the folks selling electronic focusers and see if one could be adapted to your current focuser, or your current one replaced with a ready-to-go focuser entirely. You need to realize these are quite expensive, and may be cost prohibitive for your current telescope. (Lipstick on a pig.)
A little less than halfway down this page begins Meade focusers for your viewing.
And here are Moonlite's offerings.

These were too rich for my pockets, so I went with the TekkyDave DIY, and played it by ear.
Avoid anything using a DC motor, you need a stepper motor for photographic accuracy.

N4646W

Thank you SonnyF for the links and info. I see you also reside in the PRC.

At present most of this stuff is more than we can afford. Got to figure out problem with the mount. One of the motors indicates a fault, and not sure I can afford replacing it if I can't fix it. At least the OTA works so it is not a total loss.

Ron

SonnyE Loc: Communist California, USA

I hear Ya Ron!
But do what you can and enjoy the rest.

Is the Lake up? Last time I was up there is was terribly low.

bwana Loc: Bergen, Alberta, Canada

I've found a Bahtinov mask one of my best inexpensive purchases and allows you to get a great focus. As one member of our local astronomy group says, "Focus, focus, focus...".

Process:
1) Acquire a Bahtinov mask to fit your telescope/lens. You can buy one or download a pattern and cut your own.
2) Line up your telescope/lens with a fairly bright star. I normally keep the star of interest a little off center.
3) Place the Bahtinov mask over the front end of your telescope/lens
4) Adjust the focus until the center line of the diffraction pattern is dead center (see image)
5) You've got a great focus!! Takes about 1-2 minutes once you have done it a couple of times
6) Don't forget to take the mask off before imaging! It makes for interesting results if left on.

Enjoy!

bwa

N4646W

Last seasons water shed brought the lake up almost to full. Buttt, they got funding to rebuild the dam, so they are draining it. Still high, but with all the snow fall this season, looks to be a repeat of last season, or Killer Kern will run through the summer. Lots of drownings last year in the lake and the river. Some folks just won't learn. Sure is beautiful and peaceful up here. Side note- very little light pollution , and a couple of dark sites just a few minutes from home. Got to get this rig running.

Ron

N4646W

SonnyE Loc: Communist California, USA

My Dad use to tell me, "One step at a time. Just like an old mule pullin a plow."
Not that we are old mules, but trying to see something through.
You'll get there, just keep trying.

Well, of course they are going to rebuild the dam. Couldn't do that before it filled back up.
That would have been the logical choice.
No. Wait till it's finally got enough water to be useful, THEN drain the Damn thing.
Idiots.

Well, I do hope you can enjoy the night skies. I look forward to warmer evenings.
Not the longer days and waiting for dark, but the balmy evenings.

Fools will be fools, Ron. It's Darwinism. Tell them not to, then they'll say, "Hey All Y'all! Watch this chit!"
And their Families get to live through the aftermath.
Growing up in the 1960's Isabella, and Success were two we learned to water sky on with my older Sisters Girl Scout Troop.
Family down the street we grew up on had a boat, great times!

N4646W

Yep, dumb and dumber seems to run rampart these days, especially here in the PRC. Unfortunately, a lot of them seem to be migrating to this area and bringing the gene pool with them.

I can only imagine how idyllic the area must have been in the sixties, but it sure beats the coast.

Ron

N4646W

bwa

There is a lot on different types of masks. The Bahtinof seems to be the one to use, or variations of it. How important is the "f" of the scope for the mask? The closest I can come is f5 for my scope diameter. I also ran across a site that has the software that calculates all this for a "tri Bahtinof" for individual scopes. Any experience with that mask?

Building a stepping focusing unit does seem like a way to go. Looks like an interesting project.

Thank you for all the information and help

Ron

bwana Loc: Bergen, Alberta, Canada

A lot earlier than the '60's but on the same theme (posted this morning): http://www.uglyhedgehog.com/t-517255-1.html

bwa