Louis D

Update your signature equipment list so we won't keep getting confused about what scope you intend to use these eyepieces in.

Highest power for me is determined by the exit pupil. For me, I max out at about 0.5mm to 0.7mm. Beyond that, the floaters in my eye become too problematic to see around. As I recall, you have an f/10 SCT from the other thread, so that would mean a 5mm to 7mm eyepiece would be my absolute maximum power eyepiece in your scope. In my f/6 scopes, I use up to a 3.5mm eyepiece for high power, but very infrequently. My point is, highest power eyepiece usage is highly scope dependent.

Undercuts weren't much of an issue before the advent of compression rings. However, brass compression rings can become distorted by undercuts and can actually come out of their grooves and wedge the eyepiece in the holder for good. The narrow bands in cheap, self-centering collets also won't always work with undercuts when they are not at the same depth/location relative to each other. This causes eyepiece tipping in binoviewers which makes image merging all but impossible.

That has to be what I misremembered. Place the barlow lens its own focal length away from the focal plane of the telescope, not the eyepiece the barlow's focal length away from the barlow lens. My mind is getting to be like Swiss cheese. Being confined at home 24/7 isn't helping matters.

All I can figure is I was misremembering something about this. Based on the formula, all I can figure is if the barlow focal length is extended enough, you end up with parallel rays and you've created a relay lens that you terminate with a focal reducer/condenser lens.

And that distance is the focal length of the barlow, IIRC.

The 14mm Morpheus is way better corrected in the outer field in faster scopes than the 15mm BST. On axis, the difference is much more muted. See my comparison image below taken through my f/6 AT72ED with field flattener.

The 5mm BST Starguider is pretty good for the money, and it has comfortable eye relief with a 60 degree field.

Agreed with Don above. Try turning the eyepiece upside-down and looking up into it with the illuminator turned on and inserted to see if the reticle drops back to where it should be and lights up properly. If so, you'll need to tighten a retaining ring under the reticle. You might need to tap the eyepiece to get the reticle to move.

Please clarify a couple of points for me. Is there red light coming out of the end of the illuminator's threaded barrel? Can you see the reticle in the eyepiece in daylight without the illuminator?

I've kept my ST80 refractor in a gym bag wrapped in bubble wrap in both my closet and in my trunk on trips with no ill effects for 20 years. I know there are custom, padded bags from Oklop and Lacerta for telescopes available in Europe if you want a more purpose built item.

Right, unless it's highly desirable kit like AP refractors and such.

Hopefully the 'fracs don't gang up on the poor little Mak in storage. 😲

That's probably the real reason for most commercial Newts. They aren't all that way. Here's the Takahashi Epsilon 180 ED f/2.8 Newtonian Astrograph Reflector as a counter example having its focuser right at the end of the tube:

Just an FYI, our user handles are Louis D and Dr Strange, respectively. Red Dwarf and Star Forming are our member "rankings" based on number of posts. Your ranking is Vacuum.

You should be able to observe most solar system objects, open clusters, globular clusters, planetary nebula, and a few bright emission nebula and galaxy cores from your location. Most galaxies, faint nebula, and comets tend to be a no-go from suburban skies (Bortle 5-6) because they tend to be faint and diffuse, blending in to the background sky glow. Aggressive nebula filters such UHC and OIII can help with nebula, so there is hope on that front.

As far as I know, Raul at DSA only does direct sales. I have both the DSV-1 and DSV-2B mounts, both bought second hand. His wait time for mounts can be weeks to months, if he responds to your emails at all. He seems to be concentrating on making and selling the DSV-3 mounts right now. I highly recommend the DSV-2B over the DSV-1 mostly for the axis locks. I use heavy eyepieces like the ES-92s and don't like the wild swings in altitude when swapping eyepieces on the DSV-1.

I would imagine @Don Pensack could point you to the best current contact for ordering custom made BST Starguiders if you're serious. 😉

Definitely let us know what you think of it once you've had some time to evaluate it. I've found it to be very usable with eyeglasses and mostly sharp across the field.

At this focal length, there's also the APM High eye relief Flat-Wide 84 degree 12.5mm to consider. It seems to be well reviewed except for some possible EOFB. It has no undercut on it's insertion barrel.

50x the aperture in inches for high contrast objects like double stars. Low contrast objects like Jupiter don't respond as well to high powers. Corrected meaning lacking in aberrations such as outer field astigmatism and field curvature. If you let an object drift through a poorly corrected wide field eyepiece, it will get blurry by about 50% out from center to edge, thus negating any advantage to the wider field for an undriven scope such as yours. I would pick up the 5mm, 8mm, and 15mm Starguider BSTs as others have recommended as well as a 32mm Plossl similar to the one in the kit. Later on as funds allow, I would add the 35mm Aero ED for widest field views.

Saturn's rings are apparent with just about any telescope. The difference is how sharply defined they are. If everything is well executed and collimated and seeing conditions are steady, Saturn should look like a fake cutout pasted onto the sky.

Generally, about 30x per inch is what I figure for Newtonians, so about 240x max for your 8", which is where you are today. The secondary obstruction and spider vanes tend to cut down on contrast at higher powers relative to an APO of equal aperture. In particular, you'll be severely limited by UK seeing conditions, so 100x to 150x might be more realistic for Jupiter in particular. Do you notice more detail in Jupiter at 240x than at 120x or are they simply bigger and more washed out? Saturn's rings and Mars can take more power due to being of higher contrast. On high contrast objects like double stars, you can try to push 300x or more. If you want to go for 400x, I would recommend a 12" scope minimum and steady seeing conditions. More expensive eyepieces have better lens polish leading to less scatter, better multicoatings, better stray light control, and wider and better corrected fields of view (especially in scopes faster than f/8 such as your own). However, on axis, a well executed, cheap eyepiece can still perform very well. Mainly, contrast and resolution on planets will suffer a bit.

AFAIK, the only commonly used focal reducers for visual usage are the ones for SCTs. But, they are more complex than just a simple focal reducer and are matched to the scope's design. Someday, I want to put one of the Celestron types on the back of a 127 Mak just to see how usable it is since there are no designed Mak focal reducers to my knowledge. I have a feeling it will vignette 27mm diameter field stop eyepieces at the very least.

In my experience, both the cheap 1.25" and 2" focal reducers add field curvature and some edge aberrations. They also require a fair amount of in-focus.