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Thread: 3.5mm Delos or 3.6mm Tak LE?

  1. #1
    Member RolandosCY's Avatar
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    3.5mm Delos or 3.6mm Tak LE?

    Well, the title says it all. I want a really high power eyepiece for using mainly for detecting very faint and small galaxies on my non-tracking 18" Obsession.

    I presently use a Tak LE 7.5mm (giving me a magnification of 275X) as my high power eyepiece, but occasionally I need something of a higher power. The obvious solution which I have is 2X and 3X Barlows (I own both TV 1.25" models). The problem is than on my non-tracking dob, by the time I have removed the eyepiece, put it in the 2X, and then re-insert the eyepiece with the barlow the fieldis both out of focus and gone. On such a tiny field usually there are two few stars to use for field identification and focus. That means taking off the combo, reinserting my 13mm Ethos to re-acquire the medium power field, re-insert the 7.5mm LE for the high power, and then again the same procedure, often in a very unnerving never-ending cycle.

    I do own a 7mm Nagler which is giving me quite a large field of view to use if I combine it with the 2X. The main issue is that on several tests I made, the LE 7.5 is superior to my beloved 7mm Nagler in detecting the faintest stars and (presumably) the faintest deep sky objects. So I stick with the small field of the LE for the better threshold detectability.

    By buying an eyepiece in the 3-4mm range I double the power without losing the precious extra few seconds of using the barlow, and hopefully the focusing will not shift as much preventing me from losing the field. I have read many positive things about the fantastic light transmission of the Delos, which has almost double the field of the LEs. On the other hand, I presume the 3.6mm LE will be very close in focus to the 7.5mm LE, and the light transmission qualities of the LE I own are a definite plus.

    Has anyone on this forum used either or both of these eyepieces? What are your thoughts on them?
    The Darker the Better!
    -------------------------
    18" f4.5 Obsession Classic #1934
    10" f5 Skyatcher Dob
    152mm f5.9 Teleskop Service
    Takahashi FS128
    SkyWatcher 120 f5
    Takahashi FS102
    Takahashi FSQ106N
    SkyWatcher ED80 Pro
    SkyWatcher ED72 Evostar
    Televue Naglers and Ethos

  2. #2
    Member Ivan Maly's Avatar
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    "Men... who above all else desire power."

    I'd ask if even the Delos has enough field for this (tracking manually at this mag and still being able to conduct critical observations).
    Ivan
    20" Sky-Watcher
    deepskyblog.net

  3. #3
    Member RolandosCY's Avatar
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    Ivan, once I manage to acquire the field I have no trouble with guiding even at 550X (LE 7.5mm and 2X barlows). IDepending on the position of the target on the sky I might be pushing the dob, or, more often, I will place it so that I can see it crossing the field and repeat it (it sounds tedious but it is not, thanks to the smooth movements of my well-balanced Obsession). Acquiring the field remains my biggest issue...
    The Darker the Better!
    -------------------------
    18" f4.5 Obsession Classic #1934
    10" f5 Skyatcher Dob
    152mm f5.9 Teleskop Service
    Takahashi FS128
    SkyWatcher 120 f5
    Takahashi FS102
    Takahashi FSQ106N
    SkyWatcher ED80 Pro
    SkyWatcher ED72 Evostar
    Televue Naglers and Ethos

  4. #4
    Member Ivan Maly's Avatar
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    Upstate New York
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    Oh, OK. For this reason too though I'd think that Ethos 3.7 could be your best bet... if you get blinded by all the light passing through its field (this effect gets confused with light throughput), just back off from the lens a bit. But that's not what the thread is about. I hope you'll get an actual answer.
    Ivan
    20" Sky-Watcher
    deepskyblog.net

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