DSV-3 Has Landed!
Posted 13 March 2013 - 10:58 PM
Posted 13 March 2013 - 11:44 PM
It still has a hard time keeping up with any of my vintage 60mm achromats,
Yes. Same with my AT66ED, in comparison to my Carton 60mm f/15, f/16.7. The latter is superb.
Posted 16 March 2013 - 02:33 PM
As for user notes, here goes. The slo-mo knobs are useful primarily for centering targets rather than tracking. It's important to take the time to properly balance the OTA(s). When balanced, smooth tracking is easier using appropriate clutch tension on the alt and az axes, and piloting the load with the panhandle. The axial movements are very smooth even loaded. The slo-mo motions aren't rough, but they aren't as smooth as when using the panhandle.
I was wrong earlier when I said you needed ringed scopes to reposition each OTA relative to the other. The requirement for a ringed OTA is if you want/need to use the counterbalance system with dual tubes (such as when you have a tiny tube and large tube mounted simultaneously).
That said, the alignment feature for aligning one OTA relative to the other is a little fussy, requiring an allen wrench and best done in daylight with a terrestrial target as a result. The fact that you can precisely align OTAs relative to one another is a wonderful plus, though, fussy or not.
Though the head is promoted as being capable of carrying a C11 and TEC 140 simultaneously, the OTA in the picture is an 11.2# 4.4" f/7 triplet. It gives you an idea of the scale of this mount head. A C11 or TEC 140 OTA are GINORMOUS compared to the shown OTA. I'm a little skeptical, but I'm also a guy who always overmounts. Later today I'm going to mount up the massive 6" f/5.9 achromat OTA to see how the mount plus counterweight system handles it. My ideal load for dual OTAs would be the AT111EDT pictured and a C8 OTA on the other side. A nice contrast in FOV and light grasp, and a very rewarding duet.
The craftsmanship is quite excellent. Raul Medina is a skilled machinist and a smart designer. I don't know how he can afford to make and sell heads of such quality for the prices he's asking, seriously.
Posted 16 March 2013 - 03:21 PM
That is the comical Astrotelescopes 152mm f/5.9 achromat on the DSV-3. When balanced, it actually works well. It would be better with the V-series saddle on the other side (I elected the option of both V-series and D-series saddle).
I have a DSV-1 on the way, so I may be able to move V-series saddles around between the two mounts. Also, for this "wide load" I will probably extend the tripod legs 6" to 8" to form a wider base triangle.
Pretty impressive, though, for the dimensions of the mount head, doncha think? The saggy dew shade on the 152mm is bugging me. I'm going to go out and try and shim it with some fuzzy sided Velcro tabs.
Posted 16 March 2013 - 04:46 PM
Beautiful mount and pics all the same however!
Posted 16 March 2013 - 05:16 PM
berlebach wood legs would look so much beefier wouldn't it?
Posted 16 March 2013 - 05:31 PM
Posted 16 March 2013 - 05:31 PM
Posted 16 March 2013 - 05:33 PM
Posted 16 March 2013 - 05:41 PM
Nope. Not even with the 152, though I do have the legs fully retracted on the tripod.
Posted 16 March 2013 - 06:07 PM
Posted 16 March 2013 - 06:41 PM
Never had a hint of a problem with a Sky Commander though, and now I have two of them. For that matter, Orion's inexpensive Intelliscope DSCs have been much more reliable for me than AN.
Posted 16 March 2013 - 06:44 PM
Dunno how the 152mm will do in the vibration department. Given the svelt 12# weight of the head, I didn't think it would handle the 152mm porker. But I was wrong!
Maybe tonight I'll give it a shot.
Posted 16 March 2013 - 08:18 PM
I didn't think it would handle the 152mm porker. But I was wrong!
well if I can handle my 8in ota on a dsv-1, I know that wouldn't be hard to do on your mount.
It's just that with my 8in sct when I get into high mag I have to wait a little longer than normal to have it settle down. I could put my tv gibraltar legs under then head to help...
Posted 16 March 2013 - 10:30 PM
Posted 16 March 2013 - 10:32 PM
Very good Jim.
Posted 17 March 2013 - 07:30 AM
Posted 17 March 2013 - 10:28 AM
Posted 20 March 2013 - 08:49 PM
How do you think it would function with your Antares F/15? I have a DVS-2 and I like it so I familiar with this mount. I've ordered a Skylight F/15 and I need a mount. You think the DVS-3 would work?
Posted 20 March 2013 - 10:35 PM
If it quits raining this weekend I'll give the Antares 105/1500 a whirl on the DSV-3. The Antares is very light for its length, but still has a large moment arm. The Skylight is heavier than the Antares and has a similarly large moment arm, so would likely be even more of a handful than the Antares for a mount.
Posted 21 March 2013 - 06:52 AM
... but for tracking at higher power I prefer the fluid movements of the clutched axes over the geared movements of the slo-mo controls.
Interesting. Counterintuitive to what I thought! My only concern about going to an alt/az is high power tracking...which is where I'm at most of the time with planets. I'm ust not sold yet on panhandle tracking...I would have thought the slo-mos were the answer. I need user reports specifically on observing and tracking planets for an hour or more.
Posted 21 March 2013 - 08:19 AM
I need user reports specifically on observing and tracking planets for an hour or more.
did you ever own a custom dob? no problem at all [at least for my smallish scopes]. when I first started with small scopes or even my 8in sct, at high mags it was like,"wow that planet is fast in the eyepiece," and at the same mag on a custom dob somehow it was like it slowed down and is like so easy to track by hand. OMG!
trying to track with slowmo controls on a alt/az for me is like trying to draw a curve with etch-a-sketch.
Posted 21 March 2013 - 09:52 AM
Posted 21 March 2013 - 10:51 AM
It's not quite that hard. The real problem with near-mount slo-mo knobs (whether on the DSV-3, Lapides Teegul, or otherwise) is that when you touch the knob at high magnification inevitably the energy of your contact with the knob is transmitted into the body of the mount proper and induces a vibration. From that point, the mount's ability to dampen that vibration comes into play. Long, flexible slo-mo knobs have been used on mounts since the 1950s to mitigate this source of vibration. It's also not particularly hard to smoothly track a target at high magnification using conveniently positioned and sufficiently isolated slo-mo knobs. In fact, I think there's a market for slo-mo knobs using modern vibration deadening materials in their construction.
For mounts with close-to-body slo-mo knobs, I find that these knobs are better used for framing the target in the FOV than for actual tracking. I've kind of talked myself out of longer rigid knobs for the DSV-3. While more conveniently placed for longer OTAs, I don't think they solve the vibration issue. I am still keen on a longer, more ergonomic panhandle though. I'd also like to see longer, flexible, dampened slo-mo control knobs.
I'm still very much enamored with the mount. I think it eliminates the reason for existence of the Lapides Teegul, for example. For about the same price you get a mount with 4x (conservatively) the capacity, not much more mass, a clever counterbalancing system and dual OTA capability. I think the same could be said of these mounts (the DSVs) relative to mass-produced alt-az mounts like the Vixen Porta II and Twilight II. You can get a hand made, well-engineered, customizable DSV mount (e.g., DSV-1) for about the same price or just a little more than these units.
I find the DSV line at current price levels incredibly "disruptive" and hyper-competitive. Like all artisanal businesses in our hobby though, I can see DSA ending up with waitlists. I like the way Rob Teeter handles it. He has defined production slots, presells those, and when a run is full, it's full. That way he can manage expectations and not get swamped with over-commitments. I'm pretty sure Raul Medina has a profession other than mount maker, so such a system might work well for him as demand grows (which it will) to ensure that he has work-work-life balance.
I'm considering going EQ-mountless for the first time ever for this year's OFLI "Out There" dark sky trip. I'm leaning toward putting an AT111EDT and a standard C8 on the DSV-3 for the 9-day adventure. Armed with 9V Li batteries (used in smoke detectors), I won't need a whopper multi-AH battery, solar charging panels, etc. For the first time ever, I have a realistic chance of traveling fast and light, and simple.