Sky & Telescope - July 2024 - 67

Launching the DWARFLAB app presents you with the Connect page (top left). The Book icon
at upper right of the screen goes to online help files, accessible only if your mobile device is not connected
to the smartscope through its Wi-Fi. Once connected, the main page (left) allows shutting off
the indicator lights. Tapping Photo takes you to the main shooting screen (above). There you have a
choice of shooting modes and a virtual joystick. An inset screen shows the wide-angle finder view.
horizon. As with all smartscopes, users
cannot rotate the camera to orient the
field differently.
Controlling the Dwarf II requires the
DWARFLAB app, free for Android and
Apple iOS. (I did my testing using the
Apple version.) The images it records are
sent to the user's smartphone or tablet,
and the stacked image as well as the
individual subframes are saved to the
onboard microSD memory card.
The Dwarf II has several different
operational modes, including Photo
Mode, Video Mode, Burst Mode, TimeLapse
Mode, Panorama Mode, and Astro
Mode. In Astro Mode, the Dwarf II
records deep-sky targets at full resolution,
producing 8-megapixel images,
which is larger than most other smartscopes
currently available provide. Users
can also choose a binned 2K option,
which electronically groups adjacent pixels
into a 2×2 array, effectively doubling
the pixel size to 2.9 microns. While
this generates less noise and smaller file
sizes, binning yields a coarse plate scale
of 5.98 arcseconds per pixel and pictures
having just 1,980 by 1,080 pixels.
While the Dwarf II tracks objects
very well, like any alt-azimuth mount it
suffers from field rotation as it follows
celestial targets. This causes stars to
trail in arcs around the field center over
long exposures. To avoid this problem,
the device records faint deep-sky
objects by shooting dozens or hundreds
of short-exposure subframes, limiting
the maximum exposure to 15 seconds.
Internal software automatically rotates,
aligns, and stacks each subframe live
on screen. It then saves its final, livestacked
image as a stretched, 16-bit FITS
file to the microSD card.
The individual frames of a sequence
can also be saved to the card, in the
user's choice of TIFF or FITS format, as
linear files (they look black). This allows
advanced users to stack the subframes
and process the result with their preferred
image-processing software.
An individual FITS frame shot in 4K
mode is 16.6 megabytes, while a final
stacked file is about 50 Mb. A folder
of 160 subframes (from 40 minutes of
shooting in 4K mode), plus the stacked
FITS file, amounts to about 2.7 gigabytes.
So, the included 64-Gb memory
Left: The Dwarf II has two lenses: a 50° wide-angle finder and 3° telephoto imaging lens. The compact form is made possible by a right-angle prism
below the main lens that forms a periscope-like light path to the Sony sensor at the end of the altitude axis. Middle: The 5600mAh lithium battery is
charged when installed in the device via a USB-C cable. The microSD memory card inserts into the slot covered by a rubber door. Right: The base
has a standard ¼-20 threaded socket for mounting on any camera tripod.
sk yand tele scope .o r g * JULY 2024 67

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Sky & Telescope - July 2024

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