What is Reddit's opinion of Celestron 93430 Luminos 7mm Eyepiece (Silver/Black)?

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Glad I could help :-)

> deep space photos

Oh, that's a whole different topic :-)

Imaging is complex, expensive and more sources for headaches when getting started.

See https://www.reddit.com/r/astrophotography/wiki/what_telescope - Great resource to chose the right gear.

While the 127 SLT works fine for some planetary imaging and some snapshots of other bright targets, it's not a good set for DSO imaging.

For serious deep-sky imaging, you need a mount that doesn't only track, but also counters field-rotation, e.g. an equatorial mount.

The SLT mount is a simple AltAz (Altitude Azimuth, Updownleftright) mount and not suited for long exposures due to field rotation and the (relatively) low precision.

The Maksutov has a "slow" aperture ratio, long focal length, and isn't exactly the first choice for deep-sky imaging.

While cheaper equatorial mounted and motorized sets are available, stability is key. E.g. a Celestron 130EQ-MD makes no sense. A NEQ3/CG4 is better suited, but does not really make sense long-term. E.g. Orion Sirius, (H)EQ5. The Orion Sirius wih GoTo costs well over $1000. Without a telescope. The manual CG4/NEQ3 costs $250-$300.

Combining terrestrial, stargazing AND imaging will result in a major headache. :-) In this case a decent apochromatic refractor might be the only thing that can cover all bases to some extend, but for visual, you really need aperture.

 

If you are unsure what route to take, get something smaller/cheaper first. Observe, get to know the do's and dont's of observing and imaging. Find out what you really need beyond what sounds good ~~on paper~~ont the screen :-)

 

> deep space photos

As you already seem to have a DSLR or similar, you can actually do some nice wide-field without even using a telescope.

• https://www.reddit.com/r/telescopes/comments/2ttydz/300_budget_looking_for_a_telescope/co2ivce/

• Longer focal lengths require guiding etc.

• Of course it's possible with the 127SLT to take some snapshots of brighter deep-sky objects, but not nearly as great as something like a 130pds/150pds reflector on a EQ5/EQ6 type of mount.

• For imaging questions aside the basics I am probably not the ideal person to ask, also see /r/astrophotography for advice.

 

> eyepieces

For a 127/1500 Maksutov, there are several choices.

A zoom-eyepiece is great for day-time use, but as with many zoom-binoculars/spotting-scopes, dedicated eyepieces tend to give you better contrast. Also zoom eyepieces have a narrow apparent field of view at the lower magnification, only 40° or so, making them poor overview eyepieces.

Short version:

Kit eyepieces 10mm & 25mm for now, consider a 7-8mm^1 2 for planets and a 15mm^123 to fill the gap. A 32mm for a bit move overview.

Zoom eyepieces are usually available in 8-24 or 7-21mm 1 2, but only the Baader Zoom offered a bit more field of view on the lower magnification. For day-time use a zoom is nice sometimes, but you can usually get 2-3 better fixed-focal-length eyepieces for the same price that perform better in the long run.

Long version:

• 32mm Plössl,

  • $20-$30: The largest field of view with a 1.25" focuser.
  • Some other 5" Maksutovs offer a 2" focuser/diagonal allowing some more field of view. Even simpler 2" eyepieces cost $70 and up though.
  • A 40mm Plössl is available too, but has a narrow apparent field of view, effectively not showing more than a 32mm Plössl.

• A 7mm will give you a bit over 200x. So perfect for observing moon, planets, double stars, ships - under decent conditions.

  • 7mm Plössl already have very short eye-relief. Plössl are the type of eyepieces included in the eyepiece kits. The longer ones >10mm are OK. Are you wearing glasses?
  • The HR Planetary clones, e.g. $49 7mm 58° afov are decent. Better are the BST Explorer and dual-ed eyepieces - But for a bit more you can also get a larger apparent field of view.
  • If you want to spend a bit more, you can get a 7mm Luminos ultra-wide-angle (82° apparent field of view)
  • A 6mm can work, but things will already get pretty dim, and 250x magnification only works if atmospheric seeing is great (which it usually isn't).

• One or two in-between.

  • Either just use the kit eyepieces,
  • Get a 15mm Plössl or wide-angle eyepiece, 123
  • or get some of "gold-line"^Link for example. These no-name eyepieces are sold by several names and the brand name Orion expanse. The whole set probably makes little sense. 15mm to fill the gap of the kit eyepieces. 9 and 20mm if you want to replace the cheap kit eyepieces. 6mm is a bit too much already.
  • At Aliexpress you can get a long eye-relief "gold-line" 6mm eyepiece for $18, at Amazon $40 or so.

 

Here is an overview for eyepiece stats at 127/1500. The magnification, true field of view, and the exit pupil

(True field of view: Extend your arm, extend your index finger. It covers a width of 1° in the sky: Twice the full moon- even if it seems larger when over the horizon. At higher magnification, you just see a fragment of that in the eyepiece)

(Exit pupil = amount of light exiting the eyepiece, under 0.5-0.6mm it gets too dim. 2-3mm is ideal for many deep-sky objects; 1-2mm for some of the smaller nebulae)

25mm: 60x Magnification / 0.86° field of view / 2.1mm exit-pupil

10mm: 150x / 0.33° fov / 0.8mm EP

32mm: 46x / 1.1° / 2.7mm

15mm: 100x / 0.5°-0.81° depending on the eyepiece / 1.2mm

7mm: 214x / 0.26°-0.33° / 0.59mm

More magnification is always tempting, but it will make things dimmer. Crude simulation. So usually you can see more details with less magnification, even if the planet isn't view-filling.

Atmospheric seeing^YoutubeExample often limits magnification to <=200x. The image wobbles, the higher you magnify, the blurrier and more apparent it becomes. For day-time over the horizon, this might be way more apparent, restricting you to 100-150x. You have probably seen the effect of heat-haze/heat-shimmer over a hot road or field, and that moving air is exactly what makes day-time observing at high magnification problematic.