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Meade lx65 8" (ACF) vs Celestron 8se
#21
RE: Meade lx65 8" (ACF) vs Celestron 8se
(January 12, 2021 at 6:05 pm)popeyespappy Wrote: The AVX mount was delivered yesterday. Now if Explore Scientific would just ship the damn telescope.

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Question about filters. What light pollution filter for viewing, and where does it go?

There are a variety of filters that can be found. They usually screw into the back of the eyepiece. Often, there is a special one for viewing the Moon and a Nebula filter for emission nebula (like Orion and Eagle).

The one, critical exception: NEVER use an eyepiece filter of ANY sort to view the sun. Putting the filter on the eyepiece puts it in after the light has been concentrated, which increases the likelihood of cracking with bad consequences.

Solar filters should go over the *front* of the telescope, before the first lens or mirror.
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#22
RE: Meade lx65 8" (ACF) vs Celestron 8se
(January 12, 2021 at 6:05 pm)popeyespappy Wrote: The AVX mount was delivered yesterday. Now if Explore Scientific would just ship the damn telescope.

Question about filters. What light pollution filter for viewing, and where does it go?

Nice looking mount!  Yeah, I hope you don't have to wait too long for the refractor.  Covid is messing up Chinese manufacturing.

As was mentioned, filters screw into the barrel of the eyepiece.  For 1 1/4" eyepieces, you need that size filter.  For 2" eyepieces (if your focuser and diagonal are of that size), you need a 2" filter. 

The exception is if you use a 2" focuser and diagonal, and then use a 2" to 1.25" adapter before your 1.25" eyepiece.  In that case you have the option of using either size filter, as the adapter is usually threaded for 2" filters (though you have to check that - not all are), or a 1.25" filter could go on the eyepiece.

As for which filter -- get a good one, or don't use one at all. Good ones are from Astronomik, Televue and Lumicon (get their new models. Televue's models from pre-2018 were not good, and old Lumicon were "mostly" good, but a few years they had a bad manufacturer). There may be one or two other good ones.

As for which type, go for narrowband UHC (Ultra High Contrast) filters. These pass the OIII and H-Beta lines in the green. They are often 22nm to 27nm of band-pass. I just bought the Televue one because it doesn't include any pass-band in the Red (which can give red halos on stars). I have an old Lumicon one, but I didn't like the red halos. NOTE: Don't bother using filters for galaxies or star clusters. These are for nebula only.

There is also the OIII (Oxygen-3) filter, which is amazing for certain supernova remnants like the Veil Nebula. The problem with them is that they dim the field a lot, making them better for larger aperture scopes. Yes, you can use them on yours, and it will make the Veil Nebula awesome, but you will want to use it only at low power. The OIII filters are recommended to be used at 3.5mm exit pupils or larger, which on a 4" scope would be 29 power or less. You might use a higher power on some small planetary nebula, however.

Overall I use an OIII the most on my 16" telescope, as it has the light grasp for it. But most people recommend the UHC for a refractor of your size.
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#23
RE: Meade lx65 8" (ACF) vs Celestron 8se
(January 12, 2021 at 7:17 pm)HappySkeptic Wrote: I hope you don't have to wait too long for the refractor. 

Got an email this afternoon with a tracking number for the refractor. Supposed to be here Thursday so hurrah I guess. I say I guess because Thursday is supposed to be the last clear day for the foreseeable future around here so I don't know when I'll be able to get it out and try it.

So far I have been having pretty good luck buying used. I got the scope, mount, Explore Scientific 82° 14mm Eyepiece, and a Hyperion Mark IV 8-24 zoom with their 2.25 Barlow all second hand. I need a filter for viewing from here in the city then I am going to start working on some camera gear.

How about something along the lines of an Optolong L-Pro Light Pollution Filter for viewing from home?
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#24
RE: Meade lx65 8" (ACF) vs Celestron 8se
(January 12, 2021 at 11:20 pm)popeyespappy Wrote: Got an email this afternoon with a tracking number for the refractor. Supposed to be here Thursday so hurrah I guess. I say I guess because Thursday is supposed to be the last clear day for the foreseeable future around here so I don't know when I'll be able to get it out and try it.

So far I have been having pretty good luck buying used. I got the scope, mount, Explore Scientific 82° 14mm Eyepiece, and a Hyperion Mark IV 8-24 zoom with their 2.25 Barlow all second hand. I need a filter for viewing from here in the city then I am going to start working on some camera gear.

How about something along the lines of an Optolong L-Pro Light Pollution Filter for viewing from home?

That filter might be good for general color photography, but wide-band filters tend to not be great visually.  They dim stars, reduce star sharpness, but don't increase contrast enough to make it worthwhile.  For photography, the Optolong seems to have good reviews.

Don't buy a photographic filter until you understand what sort of mounting it will use.  That will depend on your photographic hardware.  A standard 2" one would be nice (as it screws into eyepieces), but that might not be big enough for photography, or fit the filter holders/wheel you are using.  People often get rectangular filters or some other size.

Sounds like a good system!  For photography you will need a field flattener unless your camera chip is very small, but for visual your scope is long enough focal-length that field curvature isn't a big problem.  You might notice it at low powers, or if you have older eyes.
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#25
RE: Meade lx65 8" (ACF) vs Celestron 8se
Making Progress

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#26
RE: Meade lx65 8" (ACF) vs Celestron 8se
Ready for first light. As soon as it gets dark...

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#27
RE: Meade lx65 8" (ACF) vs Celestron 8se
Nice looking kit! How did first light go? It is supposed to be clear tomorrow night, when I'll take out my 5" refractor.
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#28
RE: Meade lx65 8" (ACF) vs Celestron 8se
(February 1, 2021 at 3:18 pm)HappySkeptic Wrote: Nice looking kit!  How did first light go?  It is supposed to be clear tomorrow night, when I'll take out my 5" refractor.

Not too good. I couldn't get anything to focus. Carried it out the next day and discovered I had to pull the diagonal almost completely out of the focuser to get it to focus. Not good since I don't think the barrel of the diagonal made it past the back edge of the tightening ring on the focuser. I ordered 35 and 50mm extension tubes which should get me in range, but it kind of pisses me off that it would not work with the parts that came from the manufacturer.

The good news is I was impressed with the optics once I got it to focus. I was looking at a house on a hill about 4000 feet away. Using a 14mm eyepiece, 51x, I was able to clearly see buds on a dogwood tree.
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#29
RE: Meade lx65 8" (ACF) vs Celestron 8se
(February 2, 2021 at 10:57 am)popeyespappy Wrote:
(February 1, 2021 at 3:18 pm)HappySkeptic Wrote: Nice looking kit!  How did first light go?  It is supposed to be clear tomorrow night, when I'll take out my 5" refractor.

Not too good. I couldn't get anything to focus. Carried it out the next day and discovered I had to pull the diagonal almost completely out of the focuser to get it to focus. Not good since I don't think the barrel of the diagonal made it past the back edge of the tightening ring on the focuser. I ordered 35 and 50mm extension tubes which should get me in range, but it kind of pisses me off that it would not work with the parts that came from the manufacturer.

The good news is I was impressed with the optics once I got it to focus. I was looking at a house on a hill about 4000 feet away. Using a 14mm eyepiece, 51x, I was able to clearly see buds on a dogwood tree.

Yeah, a bad "first light" experience isn't fun.

Many refractors are made with a long back-focus, so that they can accommodate cameras and filters, or binoviewers.  Knowing whether you need extension tubes or not is a learning experience.  Too bad the seller couldn't have told you this.  It is quite normal, though. 

It is worse when you don't have enough in-focus, and you have to buy new stubby diagonals (that doesn't happen these days, unless you are trying to use a field flattener).
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