Author Topic: Any help? Tasco Luminova... mount with the tremors  (Read 469 times)

Ronnie Walsh

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Re: Any help? Tasco Luminova... mount with the tremors
« Reply #30 on: February 09, 2018, 09:22:40 AM »

On a great note, I finally took the 15 seconds needed to measure the OD of the EPs. They are 1.25". So, if I am not mistaken even if I decide to invest in 2" EPs, I can purchase an adapter to handle that difference. I am very pleased by that discovery. I just assumed they were the .965". I will start perusing the internet for decent deals on some quality, though not expensive, deals.
The next logical question to ask is what type of eyepieces your 60mm has and what type of eyepieces your 90mm has.

On the eyepiece there should a letter or two, such as H, R, K, MA, etc, next to the number that designates the focal length. Knowing this for the eyepieces you have should help. If details about the eyepieces associated with your 90mm are also available then that would help too.
The 60mm (Tasco) has H25mm, H12.5mm, and SR4.5mm. The 90 (Meade) has MA25mm, and Or.6mm.

Thank you.

On a side note to the EPs, I took the Tasco mount off of the tripod. I made some plastic washers, and added some metal washers where needed. It seemed to take out nearly all of the slop. I am sure that it will still have a bit, but not as much. I am also going to hang a weight from the center. The weight is a temporary thing, because it looks like it will be clear night. Hopefully I can hunt something interesting down.

I am interested to hear what the letter designations mean. I am googling it in the meantime.

Thank you![/quote]
The "H" stands for "Huygenian," a very old design. The others, Symmetrical Ramsden, Modified Achromatic, and Orthoscopic are newer by several hundred years. These give wider fields than the "H" and generally work better.

My old scope had 0.965 "H" eyepieces. The images were quite acceptable, but the field of view was relatively narrow. The biggest potential problem would be if the eyepiece lenses are plastic instead of glass.

If the eyepieces from your larger refractor are also 1.25-inch then you should be able to use them in your 60mm. Shuttling the eyepieces back and forth between locations could be problematic, obviously. The MA25 would be the more useful of the two and I would definitely suggest you try it before buying anything else. The 6mm might push the 60mm beyond its practical limit.

Depending on how well your modifications to the mount work out, you could later consider buying a better eyepiece or two in the 15 to 20mm range, probably a lower cost Plossl design, or a Plossl eyepiece with a longer focal length, no more than about 30 mm in the 1.25-inch size. They should work in the larger refractor too.[/quote]
Interestingly enough, or maybe not for that matter, the SR4.5mm in the 60mm has shown an impressive view of the portion of the moon that fits inside the FOV. I was surprised that I could bring it into focus. The moon would drift through the FOV in seconds. LOL. It was interesting, though.

I am very curious to see how significant the difference between the two scopes is. If I can do it cheaply enough, I intend to further reinforce this mount, or replace it with an inexpensive better option. For now, though, the washers, and hanging gallon of windshield washer fluid should give us a less space-jiggling experience.[/quote]
The 4.5 is giving you about 156X. A lower power, approaching 100X, should show detail as well or better and make aiming at and tracking the Moon or a planet much easier. I do agree that high power views of the Moon are impressive, even in a GST (Garage Sale Telescope.)