Louis D

4 hours ago, Don Pensack said:

However, I passed my APM 12.5mm Hi-FW around at a star party, and everyone saw the same thing I saw--Edge of Field Brightening (EOFB) in the last 20° of the field all the way around.

Alas, because it's a better eyepiece except for the EOFB, but I couldn't tolerate the EOFB and sold the eyepiece.

I haven't noticed it despite using it quite a bit lately.  The worst premium eyepiece I've owned for EOFB is my 12mm NT4.  One night it was so bad that the graying extended almost to a point on axis.  I swapped in my 12mm ES-92 for comparison, and suddenly the sky background was evenly dark again.  I swapped back and forth a few times to make sure I wasn't imagining it.

I'll look again more critically for EOFB in the Hi-FW sometime.

4 hours ago, LDW1 said:

You mentioned a situation with your eyes yet you can still note that and other performances ?  You are amazing, better than the average astronomer.

Yes, because I wear corrective eyewear at the eyepiece, and have years of experience critically comparing eyepieces for various aberrations and other issues.  Your point is what?  Ego stroking or snidely trying to take me down a notch?  If you believe I am unqualified to discuss eyepiece performance, just come right out and say it and present your evidence to support that view.  I'm always willing to have a cordial debate on topics near and dear to my interests.

I'm well aware of my eyes' limitations and always take them into account.  I have my eyes examined yearly and get new glasses yearly.  In fact, I find it annoying when folks who don't even know if they have eye astigmatism because they haven't had their eyes examined for years make any sort of claims about eyepieces lacking sharpness.  That, or they live with small amounts of astigmatism because they don't want to be bothered with corrective eyewear.  They often forget to take that small amount of astigmatism into account when critically examining eyepiece aberrations.

That being said, it's not hard to distinguish eyepiece astigmatism from any residual eye astigmatism with correction if you are a careful examiner for aberrations.  Simply put a moderately bright star on axis and rack the eyepiece back and forth through best focus.  Any change in the shape of the star out of focus from being perfectly round is pretty much dependent on your own eye's astigmatism because I've yet to find an eyepiece that exhibits astigmatism on axis.  In my case, the change with corrective eyewear is negligible.  I just see a round Airy disk.  Now, move that same star in steps toward the edge and repeat the focus racking to observe how much the star changes shape on either side of best focus at various point across the field of view.  Astigmatism will cause the star to stretch radially on one side of best focus and tangentially on the other side.  At best focus, it may resemble a small cross rather than a point of light.  Most eyepieces exhibit some amount of astigmatism when used in f/6 or faster scopes in the last 5% of the FOV in my experience.  Only a very small number of the very best corrected eyepieces show practically no astigmatism at the edge.  My 10mm Delos and 30mm APM UFF immediately come to mind as having none at the field stop.

I'd never given it much thought, but all of my Dobs have the focuser on the right (E side) as seen from the primary end.  Thus, I pull as I track when viewing south, my typical viewing arrangement.

Compared to my Pentax XL 14mm, the Morpheus 14mm has slight edge astigmatism in the outer 10% at f/6 and faster.  However, the Morpheus has a much flatter field, but it still has a slight curvature.  However, when refocused for the edge, the Pentax is astigmatism free to the edge.  However, since I don't ever refocus while letting stars drift across the field with my undriven mounts, the Pentax loses on net.  Thus, the Pentax was relegated to my B-team case while the Morpheus was promoted to my A-team case.

That said, I prefer the APM Hi-FW 12.5mm over either.  It is wider in both AFOV and TFOV than either, absolutely flat of field, and astigmatism free at the edge.  The only annoying thing about it is that it compresses objects into the field stop instead of stretching them like most eyepieces.  That, and it is quite heavy.  I like it so much, I keep it with my grab and go kit because I tend to use it exclusively some nights when scanning the skies aimlessly to unwind.

3 hours ago, InTheWakeOfStardust said:

I love the child seat photo haha! I have definitely been guilty of throwing the sucker on the back seat of the car and just keeping it in place with the seat belt. As you say, probably not good for it at all, but I really didn't want to have to take it apart and put it back together again.

I usually just put my 8" Dob vertically in a corner of the back of my van and simply bungee cord it in place.  It works just fine.

9 hours ago, Second Time Around said:

I like the eyepiece on the left hand side of the tube looking up from the main mirror end.  This is because my left eye is my dominant one.  This means that the heat from my body doesn't waft in front of the open tube and cause turbulence and so degrade the image. 

I'm having difficulty diagramming this in my mind's eye.  Doesn't your entire body sit to one side or the other of a Dob when observing?  None it is in front of (below for big Dobs?) the tube when observing in my experience.  Could you explain a bit more how your body heat ends up wafting up in front of the open end of the tube?

FWIW, I'm also left eye dominant, so I feel your pain when using DSLRs and other devices that assume right eye dominance.  My DSLR's rear screen has all sorts of nose grease imprinted on it because of this.

Based on the Pentax XW and XL lines, which are similar to the Morpheus in that the eye relief and AFOV remain relatively constant across focal lengths, it is the upper image forming section that remains relatively constant while the lower section Smyth lenses change to achieve different powers.  The exceptions start occurring as the focal length gets longer.  I'm pretty sure the 17.5mm Morpheus has a different upper section based it having a reportedly narrower field of view and having been designed years after the first group.

Pentax XWs:

Pentax XLs:

Notice the subtle difference in the lowest lens of the upper section of both the XW 20 and XL 21?  I have a feeling the Morpheus 17.5mm is similar in having a different upper group prescription.

Also notice that the XWs added a middle element to the 7, 10, and 14 that didn't exist at all in their XL counterparts.  I have a feeling it was to better control alignment of the various edge rays across the field when going from 65 to 70 degrees.

Lastly, notice how many Smyth group variations there are across the two lines.  Apparently, that is where the designer was allowed the most degrees of freedom.  By keeping the upper section mostly constant, they could reduce manufacturing costs across multiple focal lengths.  Only the small Smyth group lenses are unique.  In the XL line, it appears that only the spacing was changed between the 10.5 and 14 and the 5.2 and 7.  For the XW line, it appears the designers were allowed to create unique Smyth prescriptions for each focal length, not just spacing.

Disclaimer: Since Baader hasn't released detailed internal lens diagrams for the entire Morpheus line, we can only conjecture about them based on outward similarities to other eyepiece lines that are better documented.

3 hours ago, LDW1 said:

It looks like your eyeglasses control everything, mine don't

If you had 2.0+ diopters of astigmatism in your eyes as I do, you'd be in the same position as me unless you wore toric contacts at the eyepiece or managed to get on with Dioptrx.  As it is, the view of stars in eyepieces with a 1mm or larger exit pupil look like star bursts to me.  This pretty much negates having finely figured optics.

1 hour ago, John said:

The 14mm and 9mm would fit into my 1.25 inch set quite well. But would the 14mm oust my 14mm Delos I wonder 

It ousted my 14mm Pentax XL mostly because it is wider and has less field curvature while being as sharp and contrasty across the same field.  When refocused, the edge of the Pentax is sharper than the significantly wider Morpheus's edge.  It was a tough choice, but I went for the Morpheus.  I would think the 14mm Delos would put up a tougher fight.

8 minutes ago, LDW1 said:

I have noticed when it comes to eyepieces on this site and CN that a half intelligent astronomer should never, ever consider an eyepiece, no matter the quality,  without checking first with the so called eyepiece experts even if it is our money to spend ! I miss that point every time, darn !  OH well, lol  !   PS:  You can teach some astronomers some of the time but you can't teach old .......... time !

I know I don't make a purchase until there is a certain amount of positive feedback from folks who know what to look for in eyepieces and report accordingly.  Early on, I made some boneheaded eyepiece choices by not doing my due diligence first and then weighing the pros and cons.

A recent example for me would be a desire to purchase the 23mm Pentax XW-85 to replace my 22mm Nagler T4, but many folks have reported that it is tight to use with eyeglasses, so I've held off.

1 minute ago, Don Pensack said:

One clarification: the measured field stop in the 17.5mm Morpheus is 21.75mm and the apparent field 72°.

That's a case where the eyepiece that was actually released, 3 years after the other focal lengths, was different than what was planned.

Well, then the difference in measured field stops between it and the APM Hi-FW is even less at just 2mm.

I received this email from Svbony this morning saying they would be at the NYAA Starfest 2023 in Ontario, Canada, with equipment to try out and sponsoring speakers.  It's apparent they want to be taken seriously as an astro supplier.  I'm glad they're becoming more actively involved in the astro community.

Dear Sir,

This is Svbony. Thanks for your continuous support and love for our brand.

From August 17th to 20th, we will be participating in the Star Party in Ontario, Canada, together with our distributor Telescope Canada as a sponsor. We sincerely invite you to join this special event. (Place: River Place Park, RR 3, Ayton, Ontario, Canada)

The offline exhibition will include the following highlights:

1.New product showcases: You will have the opportunity to see all of our telescope series, including the new SV550 122mm. At the event, you can try out our astronomical cameras and other accessories for visual or astrophotography observations, free of charge!

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We are looking forward to meeting you and spending this wonderful time together. In order to better organize the event, we sincerely hope to receive your reply. If you can attend, please respond to us before August 13th. You can also let us know if you have any other ideas or suggestions. If you haven't joined our Facebook community yet, click the link below to apply and interact with more people! 

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Cindy

Henaneshow, Zhengzhou,

5 hours ago, badhex said:

I wonder if anyone has done a shootout between the two. @Louis DI can't remember if you own both (or either) of those EPs? 

I only have the 9mm and 14mm Morpheus eyepieces.  I've thought about getting the 17.5mm Morpheus, but it's hard to justify it when I already have a 17mm ES-92, 17mm Nagler T4, and 17mm AT AF70.  That, and I tend to skip over that focal length.  The 12.5mm APM Hi-FW I have has a 19.8mm field stop diameter and more magnification, so I rarely feel the need for a slight step up in true field size and decrease in magnification that would be the 17.5mm Morpheus.

49 minutes ago, LDW1 said:

Not trying to hijack but I put together a 4 set of Celestron Ultima Edge eps to compliment my full set of Morpheus, save for the 14mm. They are about the same price but in performance they function a step or so below the Morpheus, in my opinion.

There is no Morpheus to compete with the 24mm UFF (Ultima Edge) with a 27mm+ field stop for widest field in a 1.25" eyepiece.  The 17.5mm Morpheus with a 23.55mm field stop diameter is apparently as far as they can push that design.  I won't argue that the 24mm UFF is perfect edge to edge (it isn't), but it's way better than any other long eye relief SWA class eyepiece at 24mm to 26mm in a 1.25" fitting.

As @Don Pensack said above, the 30mm UFF has no peer, Morpheus or otherwise.

14 hours ago, Stellaris said:

The objects being out of focus was my guess two, but I’m not quite sure if i need more distance between my sensor and scope, or less of it.

That's why you need to start with bright objects to be able to establish with confidence where the new focal plane resides.  Also remember that most eyepieces project a curved focal plane, so you might have out of focus edges on your sensor.

42 minutes ago, bosun21 said:

Where's the mirror? I imagine that the mirror will be no lightweight either.

It's probably under that tan piece of wood in the bottom of the mirror box.  Most big Dobs designs have a board to protect the mirror from falling objects.  I know my Tectron 15" does.

On 16/07/2023 at 13:44, ONIKKINEN said:

no need to worry about the tripod since its just 3 steel tubes so nothing fragile here

You could wrap the legs in the appropriate inner diameter pipe insulating foam for a bit of impact protection and to keep them warmer to the touch in winter.

I wrap my gear in bubble wrap and then put it in the gym bag(s) for transport.  That way, it's somewhat protected from inadvertent bumps.

Were you taking images directly onto the camera sensor before with no taking lens in between?  My guess is that the focus position changed dramatically with the 2x Barlow and 10mm eyepiece.  That, and your image scale changed dramatically, dimming the objects to where you can't even see them with short exposures.

Try out your imaging train in the daytime on a distant object.  If you get that figure out, try it out on the moon next.  If you get that working, try dimmer objects.

5 hours ago, Giles_B said:

Hopefully cooldown is not a big problem as the scope is kept in the shed.

Sheds here in Texas can heat up in the direct sun to 20 or 30 degrees F above outdoor ambient temperature.  That would be extra thermal load to dissipate at night.

1 hour ago, Bivanus said:

@Piero: Touche on the ladder 🪜 It's funny that usually I mention the collimation issues as why I shy away from Newts / Dobs totally forgetting the size & not always friendly EP positioning 😁 Please don't get me wrong, have nothing against the reflectors and only respect for those patient enough to use them 🤗

Think how unfriendly it would be to mount a 16" APO refractor if you could get one made for you at any price.  Imagine hauling that out to a dark sky site and setting it up by yourself.  I'll take dealing with an f/4 or faster 16" or larger Dob's viewing position any day over that.

For most Newtonians, I favor f/5 to f/6 to keep the tube more compact without growing the secondary too much by using a low profile focuser.

7 hours ago, Mark2022 said:

Isn't it possible to adjust white balance to balance out the yellow hue caused by the 495 longpass?

I was wondering a similar thought last Thursday except I was wondering if adding a Zhumell Moon & Skyglow (Urban Skyglow) filter or a Tiffen CC50B color compensating photographic filter to various yellow filters would yield a more neutral color balance when combined with my DSLR's automatic white balance setting.  The CC50B filter has just about the same density and color appearance (purplish) as a M&S filter despite not having that notch at yellow-orange.  Basically, cutting yellow (M&S or purple CC filter) somewhat compensates for cutting violet (yellow longpass filter).

Here are the results below:

The Baader Semi APO is fairly neutral all by itself.  It does a semi-decent job of cutting violet at night.

The M&S plus either the Hirsch #12A or cheap Chinese Yellow yields a result very similar to the Semi APO and also does a decent job cutting violet at night.  The vignetting in the cheap Yellow image is because I was using a 1.25" filter instead of 2" filter in this one case in front of the taking lens.

The M&S plus Rokunar K2/#8 Yellow looks very similar to the daylight Contrast Booster images I've seen with that weird greenish sky.  At night, it cuts all violet.

The Tiffen CC50B plus Rokunar K2/#8 Yellow is very similar in color balance to the M&S/K2 combo as I expected.  I don't recall trying this combo at night.  Something to remember to try out next time.

The M&S plus Meade #8 Light Yellow is closest to the original color balance, but doesn't do much to reduce violet.  Again, I don't recall trying this combo at night, but I doubt I'll try it since the Meade #8 Light Yellow doesn't cut any violet that I can see.

Overall, even a DSLR with sophisticated color balance algorithms couldn't correct out the weird color casts completely.

The Contrast Booster filter is basically a 495 Longpass combined with a Neodymium glass subtrate.  You can get roughly the same results with a Yellow K2 filter stacked with a generic Moon & Skyglow filter.  Transmission might be a bit lower than the CB.

2 hours ago, Mark2022 said:

Louis, was the $10 price just a lucky one off or are they readily available in the States at that price? Can't  find them in the UK and to get from the US costs about £40 - 50.

I ordered some other filters from the ebay seller at the same time to experiment with to save on shipping costs.  The cost for the K2 filter came down to $15.70 with tax and shipping.