Louis D

I found this article comparing the Baader film to the Thousand Oaks film. It appears that the Baader is sharper, wider spectrum, and brighter. I've used the Baader film for 20+ years since it was introduced. In my 8" Dob, I find I need an IR blocking filter for long viewing sessions. This shouldn't be an issue with a C90, though. Comparison images: Baader: Thousand Oaks:

Just defocus a bright star and center the circle on the now backlit crosshairs of the reticle. There's really no need for an illuminator in an eyepiece if all you're doing is centering on bright stars for alignment purposes.

Brrrr!!! 🥶

Texas shares a lot of the same problems with Australia. Of course, California has been trying to overachieve in the realm of wildfires lately. We'll see if they get heavy rains followed by landslides next.

Did you get a full refund?

In that case, rather than rehash SCT vs Mak here, read through this very recent thread:

The only one that's a Mak is the Orion Starseeker IV 150. The Celestron 6SE is an SCT. I guess your decision is made if you want a Mak over an SCT or Newt.

Well, they're both made by Synta and both are considered good performers. Orion USA doesn't make anything, they are strictly a reseller. Hopefully, others will chime in on the relative merits of each scope and mount.

Or get a 7.2-21.5mm zoom with a Baader Q-Turret 2.25x Barlow as @John has often suggested. That way, you'll have all the focal lengths between 9.6mm and 3.2mm.

That means it has a focal length of 1000mm and an aperture of 114mm. The focal ratio between these two is 1000/114 = 8.77 ~= 8.8. If you take the focal length of the scope and divide it by the focal length of the eyepiece, you'll get the working magnification. So 1000/25 = 40x, 1000/9 = 111x, and 1000/5 = 200x. Adding the 2x unit ahead of the eyepiece doubles the magnification of each combination. I would start with the 25mm and try and get Saturn or Jupiter first. Remember, they're very low in the sky, so you'll have to work quickly after sunset to catch them at all. Also, you'll need a clear sight line to the southwestern horizon. At 40x, Jupiter's moons and Saturn's rings should be obvious. By the sound of it, you might just be looking at stars in the vicinity instead and need to get the finder scope adjusted to make sure the main scope is on target as mentioned above. Once you've got one of them for certain at 40x, try moving up in power to the 9mm and then 5mm eyepieces. You could also try the 25mm or 9mm with the 2x element for 12.5mm and 4.5mm equivalents. The 5mm plus 2x isn't going to work well in your scope, so just avoid that combination.

Are you implying the Delos's upper barrel is also aluminum and only the lower barrel is brass? What has been the industry standard for the upper barrel? I know chromed brass has been the standard for the lower barrel for years, but I really have no idea about the upper barrel metal. Siebert has been using aluminum upper barrels to make his eyepieces lighter than they would otherwise appear to be. Russell uses Delrin for his eyepiece barrels that makes them even lighter yet.

In gun circles, Picatinny rails are used to securely attach accessories to the barrel via clamps, sort of the reverse of astronomy where the clamp is on the OTA and the rail is on the accessory. I have a Losmandy finder bracket that follows the Picatinny model, but with a slightly narrower rail. It's been discontinued, but it's similar to this current one: There won't be any flex with a setup like this.

The effect becomes more pronounced with more light pollution due to the narrower passband of the OIII rejecting more spurious light, increasing contrast. Losing the H-beta line doesn't seem to affect the image as much as rejecting more light pollution.

I have a late 90s Lumicon OIII that made the Veil nebula visible in exquisite detail under my Bortle 5/6 skies in my 15" Dob. Without it, I couldn't make out any of it. It also works well with my 8", but the bigger the better with OIII filters.

Probably due to the use of engineered plastic case materials in the Morpheus and brass or another dense metal in the Delos. Delrin and aluminum bodied eyepieces are both noticeably lighter than their brass counterparts. One downside to them is that the threads can be cross-threaded more easily, so filters and disassembly/reassembly can be problematic.

Optically and mechanically, Sharpstar Optics have been doing a good job of producing consistently excellent, premium refractors at affordable prices. They're usually sold under various house brands around the world. If you look at their focusers, you can usually distinguish their products from other Chinese optics houses. I have a TS-Optics 90 mm f/6.6 FPL53 Triplet APO that has excellent optical correction and refined mechanicals. It's pretty clearly an older Sharpstar.

Have you read this webpage? Semi-apo and apo lens objective examples Here's an instructive set of diagrams of various doublets and triplets: The glass types are explained in the table above it on that webpage. My takeaway from this diagram is that there is no one best solution. Refractors will always be a compromise when it comes to bringing all wavelengths to a common focus across the entire field.

Yes, the longer I observe, the more it feels like my eye is being cooked despite there being no pinholes nor excessive brightness. There is a general feeling of fatigue and soreness in my observing eye after a time without the IR blocking filter. I noticed that the Lacerta Herschel Wedge recommends using an IR block filter, so I don't think I'm losing my mind. They claim mainly for photography, but that means it's getting through if a camera sensor can pick it up: IR/UV Blocking filter and Baader Solar Continuum Filter is also recommended, especially when used for photography. If a Herschel wedge can pass IR, I have little doubt Baader Solar Film can pass it as well. Remember, too, I'm in Texas where the sun's intensity can sunburn a fair skinned person in 10 to 20 minutes during summer noon. I always wear a wide brimmed hiking hat when I'm outside in the summer for more than 10 minutes at a time, such as at fairs or when solar observing, to protect my bald spot, ears, nose, and neck:

Tried to google Lacerta Wedge in the US, I got the following hit for a Lacerta Group Sandwich Container 2-Wedge: I thought it was a prank at first, but no, it's real. It's probably most useful for staving off hunger while solar observing. 😁 Still trying to find a US retailer for the Lacerta Herschel Wedge.

Yes, all T-rings are M42 (42mm x 0.75mm thread pitch). They are not to be confused with the M42 lens mount (universal screw mount) which is 42mm x 1mm thread pitch.

Or reverse this, and put yourself on the waiting list for 15 different shops and see who comes in first with new stock. Just don't provide any payment details such as a CC number to any of them. You shouldn't have to put down money to join a waiting list, even for custom made items like AP scopes. You might wait 10+ years on an AP list, but if they decide to build a scope again, they'll work their way down the wait list and ask each person if they're still interested enough to put down a deposit at that time.

Comparing my 8" Dob to my 127 Mak, the former is easily the more versatile scope. It provides wider views, more detailed planetary images, and brighter DSO images. It also handles the weight of 2+ pound eyepieces much more easily. The Mak is much more compact and handles binoviewers more easily. I would start with the Dob and get the 127 later if you feel a need to take a scope camping or on vacation (holiday).

Perhaps it was a custom made or limited availability adapter? In 20+ years of astro shopping, I can't recall ever seeing one being advertised or reviewed. It's certainly a very nice idea for eyepieces that don't have hidden M43 (or similar) or T-threads to allow for camera attachment. It negates the need for an eyepiece clamp which are pretty dodgy anyway.

Be prepared for tight eye relief. The combination of a small eye lens (23mm) for an 82 degree field coupled with a deep recession will make it tough to use even without eyeglasses. Ernest in Russia measured the usable eye relief to be between 5 and 10mm while the design ER was 14 to 19mm. I think the uncertainty is due to CAEP (chromatic aberration of the exit pupil) where the red and blue ends of the spectrum form images at differing eye reliefs. I've noticed this with my 30mm ES-82. The exit pupil is a vague smallest circle that is red at one distance, white in the middle, and blue at the other end distance-wise from the eye lens. This also manifests itself as the ring of fire with an orange-red ring around the periphery of the view.

Probably something like an AP1200 or AP1600 mount or a Parallax HD300C would do nicely. 😉